CRATEROMORPHA CORRÜGATA. 



83 



ïext-fiffure 2. 



50 mm, high ; size of the oscuhim 

 with out-tiaring rim, 26 mm. hy 

 11) mm.; and breadth of the body 

 at base, 2o mm. l)y 18 mm. The 

 other specimen [B] is 80 mm. 

 high ; body, o4 mm. long, and 27- 

 37 mm. broad ; size of the oblong 

 osculum, 34 mm. by 16 mm. In 

 both the lateral compression of the 

 body is distinct, a fact which I 

 have not specially noticed in all 

 the larger specimens. Both the 

 small specimens show on the der- 



plia comujata ij., iVoio Outside okiiiosé. niai snrfacc of the bodv a numbci 



The arrows indicatu tlie intercumiaiinicut- 



Two small -pecimens of Craln-'naor- 



cornicfata Ij., iVoio Outside Okiiic 



arrows indicate tlie intercuimaiiniu 



ing external depressions, f nat. size. of dimple-like dcprCSsionS. SomC 



not all — of the deeper and pit-like depressions intercommunicate 

 with one another, representing an early stage in the formation 

 of intercanals. From their general appearance it is to be con- 

 cluded that the intercanals result from the breaking through of 

 adjacent external depressions, which become deeper as the sponge 

 advances in growth, and apparently not by the fusion of tubular 

 outbulgings from the sponge-wall, although the two processes, as 

 both actually occur among the Ascons, are to be considered as 

 modifications of one and the same process leading to the same 

 result. In the two little specimens under consideration, the junc- 

 tion of the body with the stalk is simple exactly as in C. ineyeri ; 

 the piercing through ol' that part seems to take place at a later 

 stage of the growth of the sponge. 



