Explanation of Plate 21 



Figs. 1-3. — Macoma moesta (Deshayes): 1, right valve, Dall's figured type of Macoma 



krausei, from off Icy Cape, Alaska; 2, 3, specimens from Dall's type lot of Macoma 



krausei. 

 Fig. 4.- — Musculus corrugatus (Stimpson), a juvenile from 204 feet. 

 Fig. 5.- — Musculus discors (Linnaeus) var. laevigatus Gray, a juvenile from 477 feet. 

 Fig. 6. — Musculus niger (Gray), a juvenile from 477 feet. 

 Figs. 7, 8.- — Thracia adamsi, new species, from 110 feet (Sept. 15, 1948), interior views 



of hinge area: 7, right valve, showing long, buttressed resilifer; 8, left valve, showing 



resilifer with portion of resilium in place. 

 Magnification: 1, X 1.77; 2, 3, X 3.15; 4, X 15.6; 5, 6, X 8.2; 7, 8, X 7.9. 



