1867.] DR. J. E. GRAY ON THE CALYPTR^IDiE. 747 



Shell solid, with high, compressed, edged, distant radiating ribs. 

 Hab. 1 



2. Calyptra ADAMSii, Recvc. 

 Calyptra depressn, Adams & Reeve. 



Shell thin, with close, sharp-edged, regnlar radiating and concentric 

 ridges, minutely striated between the ridges. 

 Hab. . 



3. Calyptra alveolata, A. Adams. 



Var. 1. Small. C\ wwzio. Reeve. C. vanikorensis, Q,aoy. C.cati- 

 cellata. Reeve. 



Var. 2. Thick, flat. C. varia, Brod. 



Shell sohd, with close, radiating, sharp-edged ribs, and more or 

 less distinct low concentric ridges. 



Hab. Philippines ; Galapagos Islands. 



4. Calyptra equestris, Chenu, Man. f. 2322, 2323. 



Patella equestris, Linn. ? 

 Calyptra liopyracea, A. Adams. 



? C. radiosa, Gould. (Bad state, with another species.) 

 C. scutulum, Reeve. 



Shell solid, with sharp-edged radiating ribs, and small radiating 

 lines between them. 

 Hab. Philippines. 



5. Calyptra stella, Reeve. 



Shell depressed, solid, with very close, flat-topped, radiating ribs, 

 which are sometimes alternately smaller. 

 Hab. ? 



6. Calyptra tectum-sinense. Gray, 1824. 



Calyptra cepacea, Brod. 



C. martiniana, C. diaphana, C. scabies, C. domitoria, C. tortilis, 

 C. cornea, C. stalloniu, C. cicatricosa, C. ossea, C. sacckarimeta, 

 C. balanoides, C. uncinata, C. hipponiceformis, C. porosa, C. cya- 

 thella, et C. Jibulata, Reeve. 



C. depressa, Adams & Reeve. 



Shell thin, very finely, regularly, radiately striated. 



Var. with expanding concentric lamina. 



Patella tectum sinensis, Chemn. ; Chenu, Man. f. 2324, 2325. 



Hab. Philippine Islands. 



I am by no means certain that the six species here distinguished 

 are distinct. C. stella seems most distinct from the rest ; but there 

 is only one specimen, and Mr. Cuming has mated it with a small 

 specimen of C. equestris. They all seem to live together at the 

 Philippine Islands. 



