ON SOME FOSSIL SPONGES FROM THE INFERIOR OOLITE. 541 



29. Descriptions of Fossil Sponges from the Inferior Oolite, with 

 a Notice of some from the Great Oolite. By Prof. W. J. 

 Sollas, M.A., E.G.S., Fellow of St. John's College, Cambridge. 

 (Read March 7, 1883.) 



[Plates XX. & XXI.] 



Since up to this time the lists of palaeontologists afford no instance 

 of a fossil sponge from the Inferior Oolite of this country*, we 

 are the more indebted to my friend Mr. "Whidborne for the rich 

 representative collection of these forms amassed by his researches. 



A preliminary account of this collection is published in the Eeport 

 of the British Association for 1882, p. 534. I now proceed to offer 

 a more detailed description of its contents. 



HEXACTINELLID^E. 

 DICTTONINA. 



EuEETlDiG. 



Emploca, gen. nov. 



A cylindrical or ovate sponge, with thick walls surrounding the 

 main excurrent canal, which, as a cylindrical tube, extends axially 

 almost to the base of the sponge, and opens unconstrictedly at the 

 summit in a circular oscule. The sponge Avails are traversed by 

 two sets of smaller canals, one incurrent, which, commencing in 

 small round ostia evenly dispersed on the external surface, continue 

 inwards obliquely downwards towards the axis ; the other excur- 

 rent, which, crossing the incurrent canals, run more or less parallel to 

 the curved upper margin of the sponge and finally open into the main 

 excurrent canal. Skeleton Euretid, i.e. a simple Dicytonine network 

 with imperforate nodes ; dermal skeleton not preserved. 



The genus agrees in general form and in the characters of the 



* On the continent one or two species have been described from the 

 Inferior Oolite, and quite lately Dr. E. v. Dunikowski (Denkschriften d. rnath.- 

 naturwissenschaftlichen Classed, k. Akad. d. Wiss. in Wien, Bd. xlv., 1882) has 

 described many loose fragments and spicules of Hexactinellid network from still 

 lower secondary strata, viz. the Lower Lias of the Schafberg, near Salzburg. I 

 append a list of Dr. Dunikowski's determinations : — Monactinellid^e, Opetio- 

 nella ? sp., Eeniera sp., Scolioraphis ? sp., Esperia sp. ; Tetractinellid^:, 

 Pachastrella ? sp., Stelletta sp., Geodia sp. ; Hexactinellid,e, Lyssakina, Stau- 

 ractinella sp., Hyalostelia sp. ; Dictyonina — Tremadictyum sp. ; Craticularia sp. 

 In England only a few Tetractinellid spicules have hitherto been described 

 from the Liassic deposits. These, erroneously ascribed to a genus of Calci- 

 sponges (Grantia) by their discoverer (C. Moore, Q. J. G. S. vol. xxiii. p. 538), 

 have been relegated to their right place by Carter. With regard to Dr. Duni- 

 kowski's memoir, I have only further to allude to a certain unfairness by 

 which it is marred : — in the first place, a complete suppression of all reference 

 to work of some earlier authors, while later ones are quoted ; and, secondly, 

 the ascription to Dr. Zittel of priority in the discovery that siliceous skeletons 

 have been frequently replaced by carbonate of lime, a priority which he would 

 be the first to disclaim. 



