CONCHOLOGY. 93 



C. pyramidata. The pyramidal Cleodora. 

 Like a pyramid, triangular, thin, transparent ; aperture 

 obhquely truncated, 



4. Limacina. One species. 



Shell papyraceous, very fragile, planorbis form, sub-car- 

 inated, involuted rather obliquely, in such a manner as to be 

 deeply and largely umbilicated on one side, and the spine 

 slightly projecting and pointed on the other ; aperture large, 

 entire. 



L. helicialis. The Helix-like Limacina. 



Thin, fragile, spiral ; the volutions united in a discoid form. 



5. Cymbulia. The Slipper. One species. 

 Shell or case cartilaginous, transparent, conical posteriorly 

 where the animal adheres, and prolonged above hke a long 

 hollow semi-cylinder, under which the animal can take 

 shelter. 



C. Peronii. Peron's Cymbulia. 



Shell shaped like a shoe, somewhat gelatinous or cartila- 

 ginous, very transparent crystalhne, oblong pointed at the 

 vertex, truncated at the base. 



6. Pneumodermon, Has no shell. One species. 

 P. Peronii. 



FAMILY I L 

 Phyllidiacea. Four genera. 

 \. Phyllidia. Three species. 

 The animals of this genus are covered with a coriaceous 

 skin, but without a shell. 



Phyllidia varicosa. Phyllidia pustulosa. 



P. ocellata. 



2. Chitonellus. Two species. 

 FormejJy classed with the Chiton ; but as the testaceous 



