474 MANUAL OF THE MOLLUSCA. 
Synonyms, Meretrix, Gray. Dione, Megerle. Cryptogramma, 
Mérch. 
Examples, C. dione, Pl. XX., Fig. 8. C. chione, Fig. 14, 
p. 26. 
Shell like Venus; margins simple; hinge with 3 cardinal 
teeth and an anterior tooth beneath the lunule; pallial sinus 
moderate, angular. 
Animal with plain mantle-margins; siphons united half-way. 
Distribution, same as Venus. Recent 1138 species. 
Fossil, 80 species. 
MEROE, Schum. 
Etymology, Meroé, an island of the Nile. 
Synonyms, Cuneus (part) Megerle (not Da Costa). Sunetta, 
Link. 
Type, M. picta (=Venus Meroé, L. Donax, Deshayes}. 
PSO is 9, 
Shell oval, compressed; anterior side rather longest; hinge 
with 3 cardinal teeth, and a long narrow anterior tooth; lunule 
lanceolate ; ligament in a deep escutcheon. 
Distribution, 11 species. Senegal, India, Japan, Australia. 
TrRIGoNA, Miuhlfeldt. 
Etymology, trigonos, three-cornered. 
li perelen bilayer ROX te, 10), 
Sheli trigonal, wedge-shaped, sub-equilateral; ligament short, 
prominent; cardinal teeth 3—4, anterior = remote; pallhal 
sinus rounded, horizontal. 
Distribution, 28 species. West Indies, Mediterranean, Senegal, 
Cape, India, West America. 
Fossil, Miocene—. Bordeaux. 
T. crassatelloides attains a diameter of 5 inches, and is very 
yonderous. 
Sub-genus, Grateloupia, Desm. G. irregularis, Pl. XX., 
feieaea 
Shell sub-equilateral, rounded in front, attenuated behind; 
hinge with 1 anterior tooth, 3 cardinal teeth, and several small 
posterior teeth; pallial sinus deep, oblique. Jossil, 4 species. 
Eocene—Miocene. United States, France. 
ARTEMIS, Poli. 
Etymology, Artemis, in Greek mythology Diana. 
Type, A. exoleta, Pl. XX., Fig. 12. . 
Synonym, Dosinia, Scopoli. 
