204 Dr. W. C. M'Intnsh on the Zoophytes of St. Andreios. XXX. — On the Invertebrate Marine Fauna and Fi'fthes of St. Andrews. By AY. C. M'Intosh. [Continued from p. 14o.J Subkingdom CCELENTERATA. Class HYDROZOA. The Hydroid Zoophytes of St. Andrews are chiefly pro-cured from the deep water of the bay, though a few ap])ear between tide-marks. Many are found in great profusion. Contrasted with the soutlrern shores, as at Devon and Corn-wall *, the majority of the Hydroids are equally common in both localities ; some occur more frequently in the one than in the other, while a third series is more characteristic of each area. Thus Sertidarella rugosa, Sertularia cujyressina, Thuiaria thuja, and Halecium muricatiim appear to be more abundant at St. Andrews than in the south ; on the other hand, Sertularia argentea and Ohelia dichotoma are probably more plentiful in the latter, together with the appearance of Tubularia at the extreme margin of low water. The cha-racteristic forms in the south are Corymorpha nutans, Aglao-phenia phana, A. pennatula, Ophiodes rnirahilis, Diphasia pinnata, and an abundance of the species of Phunularia. At St. Andrews Sertularia filicula, S.fusca, Tuhularia coronata, Cuspidella humilis, and Halecium lahrosum afford distiir-guishing features. MoreoA'er, instead of the tufted Clava squamata, so common on the littoral Fuci of the western coast, we have C. multicomis at St. Andrews on the under surface of stones ; the splendid Corymorpha nutans of the sandy voes, and the rich tufts of littoral Corynidos and Gonothyrmce of the Zetlandic region, are likewise wholly absent. Amongst the Hydromedusse, Sarsia prolifera, Forbes, occurs occasionally, and Thaumantia^ pihsella, Forbes, in great abundance on the surface of the bay in autumn. The habit of the zoophytes affords many interesting facts, especially in regard to the profusion of parasitic structures. The roots of the pol}'p)aries spring from diverse shells, stones, crabs, submerged sticks and branches. One of the most curious examples found by the fishermen in the bay consisted of a stout branch of a thorn-tree, about fom-feet in height, which had large specimens of Balanus Hameri and Ascidians clustered like living fruit on the main trunk and branches, * J. & E. Q. Couch, in their ' Cornish Fauna ; ' the elaborate catalogue of the Rev. T. Hincks in the 'Ann. & Mag. Nat. Hist.' 1861-62; and Mr. Parhtt s Devonshire Catalogue published in 1866.
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