276 MANUAL OF THE MOLLUSCA. 
CALYPTR@A, Lam. Cup-and-saucer limpet. 
Etymology, calyptra, a (lady’s) cap. 
Synonym, Lithedaphus, Owen. 
Types, O. equestris, Pl. XI., Fig. 10. C. Dillwynnii, Fig. 11. 
Shell conical; limpet-shaped; apex posterior, with a minute, 
spiral nucleus; margin irregular; interior with a half-cup 
shaped process on the posterior side, attached to the apex, and 
open in front. Surface rugose or cancellated. 
Animal with a broad muzzle; tentacles rather short; lanceo- 
late; eyes on bulgings at the outer bases of the tentacles ; 
mantle-margin simple, sides plain. Found under stones, be- 
tween tide-marks, and in shallow water. (Cuming.) 
Distribution, 50 species. West Indies, Honduras, Britain, 
Mediterranean, Africa, India, Philippines, China, Japan, New 
Zealand, Gallapagos, Chili. 
Fossil, 31 species. Carb. ? chalk—. Britain, France, &c. 
Sub-genera. Crucibulum, Schum. (Dispoteea. Say., Calypeopsis, 
Less.) 
Example, C. rudis, Pl. XI., Fig. 12.. 
Shell spinulose; internal cup entire; attached by one of its 
sides. 
Distribution, West America, Japan, West Indies. Found on 
shells, with its base worn, or smoothed by a shelly deposit. 
(Gray.) Between this section and the next there are several 
intermediate forms. 
Trochita, Schum. (Infundibulum, J. Sby., Galerus, Humph. 
Trochatella and Siphopatella, Lesson.) ‘TT. radians, Pl. XI., 
Figs. 13, 14. (=Patella trochoides, Dillw.). TT. sinensis, 
PAT A, Hie. 15. 
Shell circular, more or less distinctly spiral; apex central; 
jnterior with a more or less complete sub-spiral partition. 
Distribution, chiefly tropical, but ranges from Britain to New 
Zealand. 
T’. prisca (McCoy) is found in the carb. limestone in Ireland ; 
and seyeral large species occur in the London clay and Paris 
basin. The recent C. sinensis—the ‘‘Chinaman’s hat” of 
collectors—is found on the southern shores of England, and in 
the Mediterranean, in 5—10 fathoms water. (Forbes.) Its 
lingual dentition is given by Lovyén; median teeth broad, 
hooked, denticulatcd ; uncini 3, the first hooked and serrated, 
2, 3, claw-shaped, simple. 
CREPIDULA, Lam. 
Kiymology, crepidula, a smaii sandal, 
