1867.] DR. J. E. GRAY ON THE CALYPTRiEID^. 735 



The shells are rarely flat when the animal has affixed itself over a 

 cavity in stones or shells. 



Trochita radians. 



Trochus radians, Desh. 



Var. Dark chestnut (Chenu, Man. f. 2343). 



T. spirata, Forbes. 



Shell solid ; whorls flat, with oblique ribs ; margins of base den- 

 tated. 



Var. Shell distorted, nearly flat ; whorls indistinctly marked. 

 Had. Coast of Peru ; Valparaiso ; Straits of jNIagellan. 



2. Clypeola. 



Shell conical, circular, spiral, thin. Apex central. Whorls several, 

 well developed. Base concave, circular. Mouth large, oblong, four- 

 sided. Axis central, imperforated, spiral, exposed to the apex of the i^ / ajjii 

 cavity. Periostraca horny, thin, lamellar. ri'^ 



A Troehila with somewhat the appearance of a Mitrella. 



* SkuU depressed, smooth. 



1. Clypeola magellanica. >\ w 



Trochita clypeolum. Reeve. 



Shell thin, conical, depressed, smooth, covered with laminar folia- 

 ceous periostraca ; base nearly flat. 

 Hub. Magellan Straits. 



2. Clypeola tenuis, n. s. 



Shell thin, conical, depressed, smooth. 

 Hab. New Zealand. 



** Shell high, conical ; whorls costate. 



3. Clypeola corrugata. 



Trochita corrugata. Reeve. 



"T. spirata, var.," Reeve; Chenu, Man. f. 2347, 2348. 



Calyptrcea pileus, Lamk. ; Deless. Icon. t. 34. f. 2. 



Shell high, conical, acute ; whorls flat, obliquely costate, or nearly 

 smooth ; base deeply concave. 

 Hab. Peru. 



Var. IcEvis. Shell smooth and thin ; the spire of the column of 

 one specimen more exposed and open. 



Hab. Falkland Islands. , . 



3. Trochella. r /-»g^^ 



Shell obliquely conical, depressed. Apex subcentral. Whorls 

 well developed, covered with a horny lamellar periostraca. Nucleus 



