'94 



W. J. SOLLAS ON THE STRUCTT7KE AND 



be polymorphic, fixed or free, with thick fibres, which were pro- 

 bably subgelatinous (!) in the living state ; the distinction of its 

 canals into two groups is noticed, the one longitudinal, and opening 

 into a central ostiolc or upon a plane surface, and the other trans- 

 verse, terminating in the ostioles scattered on the lateral surface. 



Nine species are described and figured, all of them, with one ex- 

 ception, which is assigned to Miinster, being claimed as new. 



Table of Species. 



S. 





Goldf. 



punctata... 



Mlmst. 



piriformis 



Goldf. 



excavata ... 



»> 



pr&morsa . 





pistillumt. 



» 



incrassata . 



»> 



cervicornis 



>> 



ampallacea 



)> 



Quader Sands. 



f Chalk (?) 



1 Jura Kalk*. 



? ? 



? ? 



Firestone. 



Greensand. 



Quetllinburg. 



Goslar. 



Charaont. 



Streitberg. 



? 



? 



Paris, Courtagnon. 

 Coesfeld, Westphalia. 



? ? [ 



p. 



PI. 



% 



221 



66 



14 



>> 



» 



13 



16 



6 



7 



97 



35 



10 



17 



5) 



8 



>j 



?> 



9 



!J 



»> 



10 



)> 



32 



5 



18 



6 



11 



98 



35 



11 



>> 



>> 



12 



1831. Deshayes. ' Description des Coquilles caracteristiques des 

 terrains,' p. 255, pi. xi. figs. 1 and 3. 



This author simply notices the occurrence of Svphonia costata and 

 S. pyriformis in the Cretaceous strata. 



1831. Benett. ' Catalogue of Organic Eemains of Wilts,' pp. 8, 9, 

 pi. 1 to 8. 

 Miss Etheldred Benett describes and figures a large number of 

 fossil sponges, including several forms of Siphonia, from the green- 

 sand of Wilts. They are all placed in the same genus Polypo- 

 thecia, Benett, a somewhat heterogeneous mixture of forms, grouped 

 together apparently on insufficient grounds of resemblance, and 

 separated into species on insufficient degrees of dissimilarit} 7 in 

 external form. Her drawings, however, are very valuable, since 

 they present us with what appear to be two gradational series of 

 Sij)honice, diverging from S. pyriformis into JS. costata on the one 

 hand, and into Polypothecia eccpansa on the other. The latter 

 series is the least complete ; but it appears to mark a passage from 

 S. r pyriformis, through an open cup-like form (P. compJexa) resem- 

 bling a Siphonia costata opened out, to a wide shallow saucer-shaped 

 species P. expansa, which resembles, at least superficially, some 

 forms of Corallistes. The other series commences with P. tphaaro- 

 cephala, which is simply a smooth ovoid specimen of S. pyriformis ; 



* The occurrence of this species in the Jura Kalk, of which the figure leaves us 

 in no doubt, is a very interesting observation. Goldfuss remarks that it is one 

 of the very few fossils common to the Chalk and Jura Kalk. 



t This is suhsequently identified with Jerea pyriformis, Lamx. 



