30 JOURNAL OF CONCHOLOGY, VOL. I3, NO. 2, APRIL, I9IO. 



When the animal is in full activity, during the rainy season, these 

 lobes are in constant movement from side to side over the surface of 

 the shell, contracting and expanding to their full length. Passing to 

 Euaustenia and Parvaklla, more closely allied to Macrochlaviys than 



C a. 



Fig. 2. — Shell lobes. B'. — Euaustenia cassida Hutton. 



View of right and left side. 

 C. — Cryptaiistenia succinea Reeve. 



From life, natural size. 

 Ca.— Ditto. 



From spirit specimen, right and leftside, X 2. 



any of the other genera w^e are dealing with, and to Cryptaustenia, 

 both with well formed shells, the shell lobes have become much 

 broader, given off lower down on the side of right dorsal lobe, form- 

 ing on the right side of the animal a broad rounded lobe, and on the 

 left side, parallel with the mantle zone and above the left neck lobe, 

 another broad lobe, but you must note they are not united. They can 

 be expanded to such an extent as to come in contact, and thus they 

 completely hide the shell. 



In Austenia we have a somewhat similar form of shell-lobe, only 



