38 MICROSCOPICAL OBJECTS FOUND 



If I am correct in my interpretations of his 

 views, as gathered from his own illustrations, 

 they differ materially from those to which I have 

 been led, on a close and careful examination of a 

 great variety of specimens. 



I am disposed to believe that the calcareous 

 portion, in which only the foramina occur, is 

 a distinct and perfect structure, produced on 

 a similar plan to that on which a mollusk 

 forms its shell — a secretion from an inner skin 

 or membrane, which separates the lime from 

 the ocean, and contributes the animal matter 

 required to render the calcareous particles co- 

 herent.* The inner membrane, which envelopes 

 the soft gelatinous tissues of the living animal, 

 is firm and strong, capable of great tension, 

 so that the creature has the power of projecting 

 it through the foramina in the same way as the 

 Echinoderms push their processes through the 

 ambulacral pores, possibly by the injection either 

 of water or of some animal fluid. But I believe 

 that this skin has no more to do with the calca- 



* If it is not ultimately found to be a development of 

 epithelial cell-structures, like those in shells, so ably investi- 

 gated by Dr. Carpenter. 



