486 Proceedings of the Royal Iri^h Academy. 



XXIV. — On" YETULiisrA stalactites (0. S.) and the Skeleton of the 

 Anoiiocladina By W. J. Sollas, M.A., D.Sc, Professor of 

 Geology, &c., Trinity College, Dublin. (Plates III. and IV.) 



[Read, February 23, 1885.] 



The Anomocladina, one of the four families of Litliistid sponges, 

 established by Zittel,^ is a small and compact group, presenting 

 several characters of considerable interest. With a wide range in 

 time, it is poor in genera and species, and in its present distribution 

 confined to a single locality. Thus it first occurs in the Silurian 

 system, three genera having been described from beds of Wenlock age 

 in Europe and jN^orth America ; it is represented by three or four 

 genera in the Jurassic, one of these ranging into the jSTeocomian, and it 

 survives at the present day in a single genus, v^ith a single species, 

 Vetulina stalactites, which was first made known to us by Oscar 

 Schmidt,- from specimens obtained by the " Hassler" expedition, at 

 a depth of one hundred fathoms, off Barbadoes. The " Challenger" 

 expedition, though it brought home several Lithistids from various 

 localities widely distant from each other, did not obtain any specimens 

 of this family. A much earlier found example than those described 

 by Oscar Schmidt, however, exists in the Bristol Museum, where I 

 found it without a label, side by side with Bactylocalyx pumiceus, 

 Stutchbury; and I have little doubt that it was placed there by 

 Stutchbury himself, who probably obtained it along with Dactylocalyx, 

 as dredging in one hundred fathoms was unknown in Stutchbury's 

 time. It is probable that the Bristol specimen, which is much larger 

 and finer than that figured by Schmidt, was obtained from shallow 

 water, i. e. not deeper than the Coralline zone. I Avas in the midst of 

 preparing illustrations for an account of this specimen, which I had 

 recognized as a recent Anomocladina, when Schmidt's work appeared, 

 and as my method of studying Lithistid sponges were not then suf- 

 ficiently advanced to enable me to supplement Schmidt's observations, 

 I gave up all idea of publishing on the subject. Since then my atten- 

 tion has been recalled to it, partly owing to the appearance of an 

 important Paper by Zittel,^ throwing doubts on his previous statements, 

 and indeed recalling them, and partly owing to my having devised 

 better methods for studying the Lithistids, so that I can now describe 

 the skeleton of Vetulina with greater accuracy, and in greater detail, 

 than has hitherto been possible. 



In Zittel's first account of the Anomocladina we find them defined 



1 Zittel ; Studien ii. fossile Spongien, ii. abth. Lithistidse, 1878. 

 ^ 0. Schmidt; Die Spongien des Meerbusen, von Mexico, 1879. 

 ■^ Zittel ; ii. Astylospongidse und Anomocladina. J. B. Mineral, 1884, ii., p. 75. 

 Translated by W. S. Dallas, Ann. N. H. (5) xiv. pp. 271-276. 



