212 EXPLANATION OF 



Digitations or Claws. Finger-like lobes ; from 

 digit us, a finger. 



Dextral. Righthanded, turning round the pillar 

 from left to right, the usual course of the 

 wnorls ; from dextra, the right hand. 



Dorsal. Belonging to the back ; from dors um, 

 the back. 



Dentated. Toothed ; from dens, a tooth. 



Diaphanous. Capable of transmitting light, 

 transparent ; from the Greek 5ia (dia) 

 through, and 0<uvw (phaino) I appear. 



Decorticated. Having the bark or outer skin 

 taken off; from de, off, and cortex, 

 bark. 



Dissepiment. A division between two chambers 

 in a shell ; from sep es, a hedge, and dis, 

 a prefix signifying division. 



Decussated. Crossed like an X ; from decussis, 

 the mark X (ten.) 



Disk. The convex part of the valves between 

 the umbones and the margin. 



Effuse. Having the lips separated by a sinus or 

 gutter, so that if the shell were filled with 

 water, it would flow out at the sinus be- 

 fore it reached the margin ; from fus us, 

 poured out. 



Epidermis. The membranaceous covering of 

 some species of shells ; from the Greek 

 em (epi) upon, and deppa (derma) a skin. 



Equivalve. Having equal values ; from equ us, 

 equal, and valve. 



Equilateral. Having both sides equal ; from, 

 equ us, equal, and latera, sides. 



