Mr. J. Morris on the Excavating Sponges. 239 
XXV. — Observations on Mr. Mdxicock^^ paper on the Excavating 
Sponges. By John Morris, F.G.S. 
In the interesting communication " On the Excavating powers 
of certain Sponges/^ &c. which appeared in the May Number of 
the ' Annals/ Mr. Hancock appears to have overlooked a paper 
published some time since by an Italian naturalist in which the 
same facts are fully and clearly described. Had this paper been 
more generally known, probably "the prevailing belief that Cliona 
does not excavate the chambers in which it is found, but that 
they are formed by worms or by decay," &c., might have been 
somewhat shaken, and " the matter which has remained up to the 
present time in obscurity " more clearly defined. It may there- 
fore be interesting to some of the readers of this Journal to give 
a short abstract of what was previously known on this subject, 
not merely for advocating the priority of discovery, but as 
strengthening the opinion as to the excavating power of these 
bodies, so admirably illustrated by Mr. Hancock*. 
Ten years have elapsed since Dr. Nardo communicated, in the 
name of his brother, to the Scientific Congress held at Pisa in 
1839, a paper " On a new genus of Siliceous Sponges, named 
Vioa, living in excavations formed by itself in stones and in the 
shells of marine mollusca, boring them in every direction.'' This 
sponge consists of numerous small very fine acicular siliceous 
bodies arranged irregularly in a fleshy but not mucous substance, 
of a yellowish, orange or purple colour, permanent or fugacious 
according to the species. At certain periods of their growth, 
these sponges emit small germs visible to the naked eye, which 
transported by currents attach themselves to stones or marine 
shells, and commence to form passages in their substance, rid- 
dling them in every direction, so as even sometimes to destroy the 
stone or shell, leaving the sponge isolated and free. Dr. Nardo 
observed the following species all obtained from the Adriatic, and 
named by him Vioa typusj coccinea, Clio, Pasithea-f. 
At a subsequent meeting of the same Congress held at Milan 
in 1844, M. Michelin, whose attention had been previously di- 
rected to the point, read a short notice on the same subject, in 
which he alluded to the traces of an organized zoophytic body 
* It is but justice to Mr. Hancock to state, that his description of the 
means by which these sponges perforate calcareous substances is both novel 
and interesting. 
f Atti della prima riunione degli Scienziati Italiani tenuta in Pisa. 1839, 
p. 161 ; Pisa, 1840. A fuller notice of this paper is in (he ' Annali delle 
Scien. del Reg. Lomb.-Venet,' vol. ix. p. 221 ; see also Revue Zoologique, 
1840, p. 27. In the same journal (p. 343) is M. Duvernoy's description of 
Spongia terebrans^ inhabiting the valves of Oslrea hippopus, Lam. 
240 Mr. J. Morris on the Excavating Sponges. 
inhabiting the tubular and vesicular cavities in the shell of Pla- 
cana sella, but uncertain as to what family it really belonged. 
The Prince of Canino, President, appointed a commission, con- 
sisting of Drs. Riippell and Nardo and Prof. Gene, to express their 
opinions on the fact, and Dr. Nardo in their name made a report, 
from which the following remarks are abridged. 
The peculiarity described by M. Michelin consists in having 
noticed between the two faces of the superior valve of Placuna 
sella, on account of its transparency, a kind of arborescence with 
dichotomous and anastomosing branches, having the inferior 
branches thick and decreasing towards their extremities, which 
are generally sharp and forked. 
On the inner layer of the shell no pores were observed commu- 
nicating with the branches, but on the outer layer are numerous 
small perforations serially disposed and corresponding with the 
articulations. These cavities have been produced by a perfora- 
ting parasitic animal which has introduced itself into the sub- 
stance of the valve, and which in consequence of a greater resist- 
ance or hardness of the inner layer in contact with the animal of 
the Placuna, has been compelled to extend itself horizontally, so 
as to form the arborescence described. On some parts of the 
surface may be observed a few attempts at perforation which have 
been arrested by a new layer of solid matter. In the Milan city 
museum is a fine specimen of Placuna having both valves per- 
forated. The large size of the holes in this shell has allowed a 
portion of the animal filling the cavities to be carefully examined. 
It belongs to the class of sponges, and specially to the genus 
Vioa, which Dr. Nardo first described in his memoir on the per- 
forating sponges, published in the ' Annals of Science of the 
Lombardo- Venetian Kingdom*.^ From the form and arrange- 
ment of the siliceous spiculse, imbedded in the substance, sharp 
at one end and rounded at the other, it should be arranged (ac- 
cording to the system of Dr. Nardo) in the second order of sili- 
ceous sponges, the ninth family Vio'ida, and the first subfamily 
Vio'ina. This species appears to be distinct from all those pre- 
viously known and described, and may therefore bear the name 
Vioa Michelini. Dr. Nardo further adds as an important fact, 
that it is not only the Placunce which have been attacked by this 
kind of sponge, but also univalve shells ; and mentions a large 
specimen of Voluta in the Milan museum, which is perforated 
by a species of sponge distinct from the Vioa Michelini, as re- 
gards its mode of development, which although serial and den- 
dritic, has the vesicular and articulated cavities smaller and bored 
on both sides. 
Dr. Nardo concludes the report with some remarks relative to 
* Sec the volume previously quoted. 
Mr. J. Morris on the Excavating Sponges. 241 
the genus Vioa, as well as to some inaccuracies of those authors 
who have written after him. He mentions that Dr. Johnston has 
not even suspected the Halichondria ccdata (which is a Viod) to 
be a perforating sponge ; and also opposes the opinion of 
M. Dujardin, who thought that the perforations in shells and 
stones (which he. Dr. Nardo, had proved to be the work of a 
sponge) were at first occupied by small species of Annelides, and 
that the sponge subsequently inhabited their cavities. Dr. Nardo 
does not think that the name Cliona ought to be preferred to that 
of Vioa proposed by him, because Dr. Grant, in establishing his 
genus, did not consider it to be a sponge, but a polype having 
eight tentacula ; and he consequently proposes that the Spongia 
terebrans, Duvernoy, which M. Dujardin regards as a Cliona, 
should be named Vioa Dujardinii, if however it is distinct from 
the species already described*. 
Since the publication of this report for 1844, M. Michelin has 
observed a valve of Meleagrina margaritifera, Lam., and speci- 
mens of the genera Conus and Fusus perforated by species of 
Vioa, as well as a valve of the fossil, Trigonia Dadalea, Park. 
M. Michelin has also noticed traces of the same genus on frag- 
ments of fossil shells from the chalk of Orglandes and the supra- 
cretaceous beds of Grignon (Revue Zoologique, 1846). 
The following species of Vioa appear to be identical with two 
of those described as Cliona by Mr. Hancock. 
Vioa Nardina, Michelin, Rev. Zool. 1846, pi. 1. fig. 1. 
V. dendritica, dichotoma, ramosissima, utriculis et tubulis compo- 
sita ; utriculis vel rotundis vel ellipticis in seriebus eleganter dis- 
positis, inter se junctis per tubulos exiguos interne rugosos ; tu- 
bulis terminalibus, acutissimis, ssepe furcatis. 
Inhabits the upper valve of the P lacuna placenta. Lam. 
This species is identical with Cliona Fryeri, Hancock, Ann. 
Nat. Hist. 1849, p. 338. pi. 14. f. 2 ; and that author described 
it as imbedded in the same shell. 
Vioa Michelini, Nardo, Rev. Zool. 1846, pi. 1. fig. 2. 
V. dendritica, dichotoma, divaricata, utriculis et tubulis composita ; 
utriculis numerosis, vesiculosis, subpolygonis, interne rugosis, ve- 
tulis maximis, junioribus parvulis, elongatis, deinde subrotundis, 
per minutissimos tubulos junctis et anastomosantibus. 
Inhabits the upper valve of P lacuna sella, Lam. 
This species is the sam'e as the Cliona spinosa, Hancock, Ann. 
* Atti della sesta Riunioiie degli Scien. Ital. tenuta in Milano, 1844, 
pp. 372, 428, and Revue Zoologique, 1846 ; see also Annali delle Scien. del 
Hep. I.omb.-Ven. 1845, p. U. 
242 Mr. J. Alder on the Branchial Currents 
Nat. Hist. 1849, p. 339, pi. 13. f. 5, and which he also found 
in the valves of Placuna sella. 
At the Scientific Congress held at Lucca (1843), Dr. Nardo 
proposed a new classification of the Spongiadce, dividing them into 
five families, under the names of Corneo-spongia, Silico-spongia, 
Calci-spongia, Corneo-silici-spongia, Corneo-calci-spongia, these 
famihes containing thirty genera*. 
XXVI. — On the Branchial Currents of the Bivalve Mollusca. 
By Joshua Alder, Esq. 
To Richard Taylor, Esq. 
Dear Sir, Newcastle-upon-Tyne, 16th August 1849. 
It was not my intention again to have troubled you concerning 
those points in the oeconomy of the Bivalves about which Mr. 
Clark and I are at variance, but the concluding paragraph of that 
gentleman's letter, in which he claims to have set at rest the use 
of the anterior siphon in the genus Kellia, demands a few words 
from me, lest my sileuce should be taken as an acquiescence in 
such a statement. Perhaps I am also entitled to a reply to the 
two new arguments by which my opinions are attempted to be 
disproved. 
Mr. Clark has at length given us a distinct statement of his 
views with respect to the admission of water into the branchial 
cavity of the bivalves, which he attributes to the opening and 
closing of the valves alone, and not to the action of cilia. Had 
this been stated at first, some misunderstanding might have been 
avoided. Undoubtedly a branchial current entering by a special 
aperture, whether anterior or posterior, cannot be accounted for 
by the opening and shutting of the valves. To explain such a 
current the existence of ciliary action is required ; but I was un- 
willing to believe that a gentleman of Mr. Clark's information 
could entirely have discarded it. However, instead of arguing 
this point further, I shall take the liberty of giving the result of 
some observations made upon two or three species of bivalves 
since the publication of my last letter. 
A small specimen of Modiola vulgaris, placed in a glass of 
sea-water, gradually expanded the margin of the mantle beyond 
the shell, and protruded the excretory siphon. When these were 
* Atti della quinta unione degli Scien. Ital. tenuta in Lucca, 1 843, p. 436. 
The details of this paper have not I believe been published ; a short notice 
however of the three first families appeared about fifteen years ago in Dr. 
Oken's * Isis.'