0)1 the Crustacea of St. Andrews. 337 membrane (fig. 34, ee), while the whole of the inner part of the skeleton was imbedded in sarcode charged with minute cells and granules (fig. 34, J J), among which could be per- fectly distinguished the monociliated spongozoa, isolated (pro- bably from the force used in tearing the specimen to pieces for examination), and in the aggregated globular forms of the ampullaceous sacs of the species (fig. 36, c, c?, cj)y both of which corresponded in appearance and measurement with the like in the parent sponge, which had been previously examined, measured, and sketched for this reference, and may be found among the illustrations (PI. XXI. fig. 23). Thus the sponge-ovule, from its first appearance to its final development into the perfect sponge, had been completely traced ; and thus its apparently chaotic mass had passed into definite forms by that mysterious power whose manifestations only we can comprehend. [To be continued.] XL. — On the Invertebrate Marine Fauna and Fishes of St. Andrews. By W. C. M'Intosh. [Continued from p. 274.] Class CRUSTACEA. Order Podophthalmata. The stalk-eyed Crustacea of St. Andrews are chiefly north- ern in type ; and though the species are not numerous, many are very plentifully represented. The most important forms here, as elsewhere, are the edible crab and the lobster. Both are caught in considerable numbers along the border of the rocks by means of the ordinary crab-pots, which are generally baited with fragments of grey gurnards and other fishes of little value. The most successful ground is off the East Rocks, though a veiy large lobster in the jMuseum of the University was procured to the north of the West Rocks. Some of the fishermen have an idea that if a lobster enters a trap first, none of the edible crabs will ventm-e beside it, whereas a lobster will invade the crab-pot though a dozen of the former are already there. Constant attacks seem to have diminished the numbers of both species, and especially of the lobster. I have never seen any of the latter betAveen tide- marks ; but young edible crabs are common under ledges and stones, and even in the sand at low water, their presence in 338 Dr. W. C. Mcintosh on the the latter being recognized by a depression. The common shore-crab occm-s everywhere along the rocky border, both between tide-marks and in the laminarian region. This ubi- quitous species lurks in the retired apertui'es and clefts amongst and under the rocks, especially where these have a bottom of soft sand or dark mud. In this it buries itself so as to retain moisture in the gills, while the anterior part of the carapace is uncovered, probably for quiet observation. In these situations it quite understands an attempt to capture it ; and there are few examples, if any, in which, by seizing the crooked iron with its chela3, it has allowed itself to be drawn out. On the contrary, it endeavours to escape with much effort and consider- able agility. Even when quite invisible its presence may be detected by sti-iking the rock, when the grating of the carapace is heard as the animal retreats. It is often to be found in positions which seem any thing but comfortable — amongst blackened and putrefying animal remains, in muddy and odoriferous pools tenanted by none except itself. In these circumstances the body is coated with mud, which fills up the irregularities of its conformation, and loads the abdominal feet and hairs ; yet the crab is vigorous and healthy, and out- lives sanitary apprehensions. Under almost every stone within reach of the tide young specimens occur. At low water the full-grown crabs seek the hiding-places just mentioned, or shade themselves under the blades of the seaweeds in the rock-pools. Occasionally one is found adhering to the soft body of a moulting brother and, cannibal-like, devouring the branchige, new carapace, and other soft organs with savage pertinacity, while the old shell has not quite fallen from its victim. Moulting shore-crabs are generally found alone, as if aware of their helplessness, and dreading, with some degree of correctness, the voracity of enemies and even unscrupulous relations. Very slight injury kills them in this condition ; and of com-se, for a time, they are incapable of defending themselves from even weak assailants. The shore-crab is found in pools at the East Rocks where no other marine articulate of the same class occurs ; and the water cannot but be brackish, since the pools are not filled by ordinary- tides, and fresh streams from the crags flow in the neighbom-- hood. In these resorts the colom- of the crab is not so pretty, being of a muddy green with pale limbs ; and the specimens in the highest pools are generally small. It is not surprising, however, to find them in such places, after watching their activity in the innumerable brackish lakes of the Outer Hebrides, and their evident comfort in perambulating the muddy flats even wdiere streams of fresh water abound. Crustacea of St. Andrews. 339 On land, Carcinus mceyias is, perhaps, the most active British crab, especially in regard to offence, defence, and escape. It scrambles over the rugged rocks with astonishing speed, while defending itself with its uplifted chelce ; and so fierce is it in attack, that having once seized an object with the latter the spasmodic effort is sometimes so great that the limb separates from the trunk at the base. The males frequently engage in combat ; and a fatal issue would more frequently ensue, were it not for the provision whereby hgemorrhage is speedily arrested and the lost portion repaired or reproduced. Few specimens, indeed, are quite free from injury. Some have recently repaired wounds of the carapace, others have lost an eye, an antenna, or one or more limbs» They surpass most marine animals in their powers of endm-ing life at a distance from sea-water, and may easily be kept for several weeks in a botanic vasculum. The shore-crab is strictly carnivorous and, as already men- tioned, even relishes its fellows. It is a curious featm-e in its history that it suffers serious annoyance and injury from the young of the common mussel, which plant themselves in its orbits, in the sockets of the internal antennaB, in the branchial chambers, and under the tail — in the former case often destroying both eyes. It feeds with avidity on the mussel in its adult state ; so that here is an instance of a help- less young form avenging the destruction of the mature. The shore-crab, again, is devoured by many fishes : thus in the stomach of a Coitus huhalts I have found five or six specimens, two entire and upwards of two inches across the carapace. The Cottus, however, unfortmiately came in the way of a large frogfish, which found a place for it in its capacious stomach, though nine full-grown flounders were already present. In many parts of Britain and the continent the shore-crab is used as food by man (and this is a safe-enough practice so long -as it is well boiled, internal parasites being abundant) ; but at St. Andrews it is only employed occasionally for bait. Myriads of the young of this species in the zoea-stage occur at the surface of the bay in autumn, and may easily be kept alive, so as to show the subsequent stages of develop- ment. Besides those abeady mentioned, many of the other forms are very common, such as Stenorhynchus rostratus, Inachus, Hyas, Portumnus variegatuSj the Portuni, Pinnotheres^ Eballa. and Neplirops in deep water, Porcellana^ the Paguri^ Galathea^ and Grangon between tide-marks, and in both regions Ilippo- lytej Pandalus, and Pahenion. In deep water swarms of Hgas coarctatus for the most part take the place of //. araneus. As a littoral form Palcetnon s. cit. p. 242. Common in the laminarian region. Fam. ThalassinidaB. Genus Gebia, Leach. Gehia deltura^ Leach ; Bell, op. cit. p. 225. Occasionally in the stomachs of cod and haddock. Tribe Anomuea. Fam. Galatheidae. Genus Galatiiea, Fab. GaXatTiea strigosa^ L. ; Bell, op), cit. p. 200. Not uncommon in deep water and in the stomachs of cod and haddock. Galathea squamifera^ Mont. ; Bell, o/). cit. p. 197. Very common under stones near low water, especially in pools and runlets ; occasionally in the stomachs of cod. Galathea dispersa^ Bate, Proceed. Linn. Soc, Zool. vol. iii. p. 3. Abundant in deep water, and in the stomachs of the cod, haddock, and flounder. i Crustacea of St. Andrews. 343 Fam. PaguridsB. Genus Pagurus, Fab. Pagurus hernhardus^ L. ; Bell, op. cit. p. 171. Everywhere abundant between tide-marks and in deep water. A young specimen was lodged inside a fragment of a stalk of wheat. This species has nine or ten branchige on each side, besides a rudimentary organ at the base of the first pair of foot-jaws. The latter have no branchial whips, and differ considerably from those of the Brachyura. The first pair of foot-jaws have the inner division very much elongated, almost antenniform, and bordered with long hairs, while the external portion is small. In the next pair the inner division more closely agrees with the external in length, and the whole is not very different from the same part in Carcinus mcenas minus the whip and branchia. The third pair is shorn of its whip and large flap, and has the middle segment * repre- sented by a narrow pedicle. The fourth pair has a narrow shield turned over at the free edge, and, instead of the two narrow spikes below, there is a flattened organ which forks into a narrow and a broad flap at the tip. The fifth pair has its inner division broad and flattened, and its outer small, but widened at the tip ; the median division has a very regular ar- rangement of bristles at its tip, which points or slopes inwards. The parasitic Peltogaster paguri frequently occurs on the abdomen. Pagurus cuanensis, Thompson ; Bell, op. cit. p. 178. Occasionally from deep water. Pagurus ididianus^ Thompson (?) ; Bell, op. cit. p. 180. St. Andrews Museum. I cannot speak with certainty of this form. Pagurus Icevis, Thompson ; Bell, op. cit. p. 184. Occasionally in the stomach of the haddock. Fam. PorcellanidaB. Genus Porcellana, Lamarck. Porcellana platyclieles^ Penn. ; Bell, oj). cit. p. 190. Abundant under stones between tide-marks, especially in * Corresponding to ering portion with bristles having short spikes towards the tip ; then come a series of flattened organs with truncate tips covered with spiked hairs. The fifth pair has three divisions — an inner irregular portion with hairs shortly branched on its free edge, a middle and somewhat club-shaped piece with rather stiff serrated hairs scantily spiked at the base, and a cui'iously curved and rather slender inner portion with about half a dozen finely serrated hairs on one side of its tip. The hairs on the outer border of the chelae are densely plumose ; and hence it is exceedingly difficult to clean them from mud and sand for the cabinet. Porcellana longicorms, L. j Bell, op. cit. p. 193. As common as the former, in similar, though not muddy, situations. The embryos are found in the ova in August ; and many young occur under stones in November and December. Fam. Lithodida;. Lithodes maia, L. ; Bell, op. cit. p. 165. Not uncommon in deep water, whence it is brought by the fishing-boats. Crustacea of St. A ndrews. 345 Tribe Bracetuba, Fam. Leucosiadse. Genus Ebalia, Leach. Ehalm tuberosa, Penn. ; Bell, op. cit. p. 141, Not uncommon in the stomachs of cod, and occasionally from deep water. Ebalia CrancMi, Leach ; Bell, op. cit. p. 148. Occasionally in the stomach of the haddock. * Fam. MaiidsB. Genus Inachus, Fab. Inachus dorsettensis^ Penn. ; Bell, op. cit. p. 13. Not uncommon in the stomach of the cod. Inachus dorTiynclius^ Leach ; Bell, op. cit. p. 16. Occasionally under stones near low-water mark. In the stomach of one were fragments of Uha, and in another the debris of a large sessile-eyed crustacean. The hairs on this species are shaped like the horn of the chamois; and some have a slight enlargement at the base. Hyas aranens^ L. ; Bell, op. cit. p. 31. Abundant under ledges in rock-pools, cast ashore on the West Sands after storms, in the crab-pots, and in the stomach of the cod. This species has eight branchial processes on each side — four lateral, two anterior, and one to each of the first two pairs of foot-jaws. Their structure resembles that described in Car- cinns mannas. The ova apparently of a small leech {Ponto- hdella) are often found attached to the walls of the branchial chamber. The number and variety of parasitic growths, both vegetable and animal, on the carapace of this form are remarkable. Balani of two species cover the back almost with a continuous rugose pile, adhering to the limbs, the abdomen, tlic foot-jaws, or each other. Coils of Serpuhn and hard sandy tubes of Sahelhtria interlace with these and fill up the depressions, and with the former occur on the tip of the abdomen as well as on 346 Dr. W. C. M'Intosh on the less mobile situations. Fine tufts of Sertularia pumila and Crisia ehurnea adorn the surface of the carapace in others or the parasitic algae thereon ; while IlaMcJiondria panicea forms a thick rugged crust, from which Balani^ Seijmlce^ AnomicBy zoophytes, and seaweeds emerge. Even the sockets of the eyes are invaded by the sponge. Moreover young examples are not unfrequently clothed with thick tufts of Ohelia geni- culata. It w^ould appear that it is not always on attaining full growth that moulting ceases for considerable intervals, since small specimens are found as completely covered with parasitic growths. In the rock-pools the carapace often forms a moving forest of seaweeds ; and in such specimens the shell is frequently fragile, so that the extraneous covering may be of use for protection, or else had grown with unusual rapidity, even before the carapace became fully consolidated. One old example had the internal antennae quite fixed by a hard sand-tube of Sahellaria ; and the young of the common mussel are occasionally found in the cavities for the eyes. In the young females the genital apertures are small, and the abdomen less developed ; while in the adult the latter becomes hypei-trophied, hollowed out on its ventral surface by the bending downwards of the outer edges, and touches the bases of the legs on each side. Hyas coarctatus, Leach ; Bell, op. cit. p. 35. Common in deep water, and procured in hundreds amongst the coralline d(5bris in the fishing-boats ; frequent in the stomachs of cod, haddock, and flounders. Fam. LeptopodiadsB. Genus Stenorhynchus, Lam. Stenorhynchus rostrafus, L. ; Bell, op. cit. p. 2 (as S. phalangium). Abundant in the coralline region, in the stomachs of cod and haddock, and occasionally under stones at low water. Fragments of sessile-eyed Crustacea and sand occurred in the stomachs of those examined. Males greatly preponderate. Fam. Parthenopidse. Genus Eurynome, Leach. Eurynome aspera^ Penn. ; Bell, op. cit. p. 46. A few specimens were procured from the coralline ground. Eare. Crustacea of St. Andrews. 347 Fam. Canceridae. Genus Cancee, L. Cancer jmgu^'us^ L. ; Bell, op. cit. p. 59. Abundant all round the rocky border in the larainarian region, and frequent between tide-marks. In the stomach of this species are many curious parasites, such as Teirarhynchus and EcMnorliynchus^ probably derived from its food. Sections of the carapace show internally tubular processes, apparently connected with the hairs. Genus PiRiMELA, Leach. Pirimela denticulata, Mont. ; Bell, op. cit. p. 72. Occasionally from deep water. Rare. Fam. Portunidae. Portunus depurator^ L. ; Bell, op. cit. p. 101. Dredged occasionally off the West Rocks on a sandy bottom, cast ashore by storms, or found in the stomach of the cod. Portunus marmoreus^ Leach ; Bell, op. cit. p. 105. On the West Sands after storms. Rather rare. Portunus holsatus, Fab. ; Bell, op. cit. p. 109. Not uncommon in the stomachs of cod and haddock. Saccu- lina occurs on this species occasionally. Portunus jmsiUus, Leach ; Bell, op. cit. p. 112. Occasionally from deep water, and rather common in the stomachs of the haddock and flounder. Genus PORTUMNUS, Leach. Portumnus variegatus^ Leach ; Bell, op. cit. p. 85. Abundant on the sandy ground off the West Sands. Genus Carcinus, Leach. Carcinus mannas, L. ; Bell, op. cit. p. 76. Everywhere abundant between tide-marks and in the 348 On the Crustacea of St. Andrews. laminarlan region. Occasionally used as bait. Swarms in tlie zoea-stage occur in autumn at the surface of the water in the bay ; they are almost invisible with the exception of the greenish-blue eyes. This crustacean has nine branchife : — the first rudimentary, and attached to the horizontal portion of the first pair of foot- jaws ; the succeeding, rather long and delicate organs, fixed to the second pair of foot-jaws on opposite sides of the hori- zontal portion ; while six are attached to the body of the animal, four being prominent, as in allied forms. The flabel- lum of the first pair passes between the four prominent and larger branchige and the apodematous region, so as to sweep their inner surface ; while the same organ of the second pair goes between the same portion of the shell and the fifth and sixth branchise (counting from behind), and may also affect the exposed surface of the seventh, which lies in the groove anteriorly. The long and finely curved flabellum of the third pair of foot-jaws curves externally, so as to brush all the seven. The great development of this organ, its central cal- careous bow, and long hairs are thus explained. The branchial lamina are an-anged with their edges to the afferent current, which crosses the organs at right angles to their long axes, and so impinges between the plates. The action of the broad shield of the fourth pair of foot-jaws, again, affects the ingoing stream, and plays upon the large flat surface at the base of the flabellum of the third pair. It would tend thus to spread out the long hairs of the latter, and direct the current upwards over the branchial laminae. The fifth pair as a whole would seem to be connected with the buccal rather than the respira- tory apparatus; for the curiously twisted portion (c, fig. 6, Trans. Linn. Soc. vol. xxiv. p. 88) is nicely adapted to the deep an- terior notch of the mandible, while the curved portion (a) enters the mouth above the chitinous tissue filling up the posterior notch of the mandible. The tuft of long hairs (e, loc. cit.), however, may render some assistance to the branchial portion of the fourth pair of foot-jaws in contact with it. The appendage of the mandible (a, fig. 7, o/?. cit.) seems to have a considerable influence in the prehension and direction of the food between the maxillre ; it has lateral motion as well as flexion and extension. The flexible process filling up the gap in the underpart of the maxilla, and connected with the lip beneath the latter, would seem to prevent the escape of particles in biting and deglutition. It is attached to a firm horny basis, which has free horizontal, but little or no vertical motion, except when greatly extended. In females bearing eggs the muscles on the external or On a remarhahJe kind of Air-bladder. 349 under surface of tlie intestinal tract greatly increase in size at the junction of the abdomen -with the cephalothorax. In males and females without ova the exterior of the gut is sparingly supplied with such tissue. This crab affords a good example of the " commensalisrae " of Prof, van Beneden. Nemertes carcinophila abounds on the hairs bearina* ova : and the vouns: of the common mussel and other adventitious growths are common, besides Sacculina ; l^rematode larva? in the liver and other parts. Various abnor- malities from injury also occur. The colours of the males are often remarkably bright, both on the upper and under surfaces of the carapace. Fam. Corystidge. Genus Atelecyclus, Leach. Atelecyclus sejJtemdentatus^ Mont. ; Bell, ojy. cit. p. 153. Frequent in the stomachs of cod. Genus CORYSTES, Latreille. Corystes cassivelaimus, Penn. ; Bell, oj). cit. p. J 59. Common on the West Sands after severe storms. Fam. Pinnotheridse. Genus Pinxotheees, Latreille. Pinnotheres pisumy L. ; Bell, ojp. cit. p. 12L Frequent in Mytilus modiolus. [To be continued.] XLI. — Description of a remarhdble kind of Air-bladder. By Dr. Albert Gunther, F.E.S. [Plate XVIII.] Among the specimens of mollusks purchased by the Trustees of the British Museum from the Collection of the late Dr. van Lidth de Jeude there was a preparation, Avhich, on closer inspection, proved to be the air-bladder of a fish. Although til ere was no indication as regards its origin, I have no doubt that the species from which it had been taken belonged to the Sciaenidte, a family distinguished by the singular structure of that organ. In some degree the present specimen resembles An7il (& Mar/. N. Hist. Ser. 4. Vol xiv. 25