170 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Genus MACOMA Leach, 1819. 
Shell oval, subrotund, convex; cardinal teeth narrow; no lateral teeth; 
pallial impression with a profound sinus. (Tryon. S. S. Conch.) 
Type. Macoma tenera Leach (= M. calcarea Gmelin). 
Distribution. W orl d-wide. 
Range in Time. Tertiary. 
Macoma middendorffii Dali, 1886. 
Plate 53, fig. 1. 
Proc. U. S. N. M., 7:347 and 9; pi. 4, fig. 11. 
Shell triangular, solid, with broad hinge plate, and flattened left valve. 
Posterior side flexuous, with an obscure radiating angle; anterior side 
rather longer; right valve a little inflated and higher than the left. Length, 
40; height, 45; diameter, 20. (Dali.) 
Type in U. S. N. M. Type locality, Bering Sea. 
Range. Bering Strait to Aleutian Islands and Chirikoff Island, 
Alaska. 
Macoma incongrua Martens, 1865. 
Plate 42, fig. 10. 
Ann. Mag. Nat. Hist., 16:430. Conch. Iconica, Tellina; pi. 27, fig. 146. 
T. testa trigona rotundata, convexa, solidula, obsolete concentrica 
striata, opaca, albida, prope vertices subfasciate et facie interna media 
ochracea; antice rotundata, postice subrostrata, margine ventrali postice 
ascendenta; flexura distincta; ligamentum superficiale, dimidium marginis 
dorsalis postice, occupans; dens cardinalis valvae sinistra unicus crass- 
iusculus, valvae dextra duo, posterior bifidus; margo cardinalis incras- 
satus; sinus palliaris magnus, per totam longitudinem cum litiea palliari- 
concretus, in valva sinistra musculum anticum attengens, in dextra ab eo 
sat remotus. Length, 33; alt. 27, crass, 15 mm. (Martens.) 
Shell small, white, trigonal, convex, solid, concentrically and irregu¬ 
larly striated, with a very thin epidermis; posterior side subacuminate; 
angle obscure flexuous conspicuous, anterior side rounded and longer 
than the posterior. Cardinal teeth small, no lateral. 
Type locality, Yokohama, Japan. 
Range. Arctic Ocean to San Diego, California. Also Japan. 
Macoma brota Dali, 1916. 
Plate 9, fig. 2. 
Proc. JJ. S. N. M., 52 :413. Zool. Beechey’s Voy., Moll.; pi. 44, fig. 7. 
Shell subovate, dull white, striated; posterior side strongly flexuous, 
with obscure radiating angle, postangular area convex, with dorsal margin 
