2 Mr. AY. J. Sollas on Stauronema, a new 



same species, it is easy to see how " dreadful " (gi-ausliclie) 

 the treatment must inevitably be which proceeds upon such a 

 basis. 



At the present day, however, things are far otherwise Avith 

 the palaeontologists ; the microscope and the lapidary's lathe 

 will give us most of the details we require to know concern- 

 ing the structure of the fossil forms ; and as regards the 

 recent ones, we are licre still better off since tlie researches of 

 Carter and O. Schmidt have given us a scientific knowledge 

 of the organization of a vast number of species, and a good 

 working classification of these into orders, families, and genera. 

 The key to the fossil sponges has thus been placed in the 

 hands of the paleontologist ; and if he dpes not henceforth 

 make good use of it, he will fully deserve the censure which 

 Schmidt has passed so severely upon his predecessors. 



In consequence of the assistance and advice which I have 

 received from my friend ]\Ir. Carter, I have been encouraged 

 for some time past to work out the alliances of some of the 

 commoner fossil sponges ; and, as a result, I am now able to 

 state that Siphonia pyriformis and costata possess the struc- 

 ture of a Lithistid sponge, and are closely related to the ex- 

 isting species Discodermia pohjdiscus (Bocage) [Dactylocali/w, 

 Bowerbank), tliat Stromatopora concentrica and some other 

 species of this genus show no affinities to the Foraminifera, 

 but are Vitreohexactinellid sponges closely resembling Dacty- 

 localyx pximicetis (Stutchbury), and that Manon macropora 

 and a sponge called Clienendopora in the Cambridge Museum 

 belong to the Holorhaphidota (Carter), or sponges whose 

 skeleton consists of acerate spicula closely bound together 

 into a fibrous network. These results, which have been fully 

 confirmed by Mr. Carter *, I hope to publish in full in the 

 course of a few months ; while in this paper I shall confine 

 myself to an account of a new genus of the Vitreohexactinel- 

 lidaj occuiTJng in the fossil state in the Gault of Folkestone. 



In examining a collection of various fossils brought by' 

 Mr. Jukes-Browne from Folkestone, to illustrate his paper on 

 the Cambridge Upper Greensand, I was much struck with 

 some curious forms, which were said to be Ventriculitce 

 split into halves down the middle ; the regularity of the 

 edges, however (which in such a case should have been broken 

 ones), seemed to preclude such an idea, and rather suggested 

 that the forms in question were in a complete state. I wrote 

 therefore to the Folkestone collector, Mr. John Griffiths, re- 



* Except •w'ith regard to S. concentrica ; Mr. Carter has shown that 

 some Stromatnpnrrp are allied to Hydractinia. 



