Mr. J. Morris on the Excavating Sponges. 239 
XXV.— Observations on Mr. Hancock’s paper on the Excavating 
Sponges. By Joun 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 im 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 typus, coccinea, Clio, Pasitheay. 
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. 
+ Atti della prima riunione degli Scienziati Italiani tenuta in Pisa, 1839, 
p- 161; Pisa, 1840. A fuller notice of this paper is in the ‘ 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 Ostrea hippopus, Lam. 
