MACOMA. 93 



three fourths inch; height, three fourths of an inch; In-cadth, eleven 

 twentieths of an inch. 



Sent to me by Dr. L. M. Yale from Martha's Vineyard. Gull 

 Island {Smith). 



It is a proportionally shorter and broader shell ; but its most o)> 

 vious mark of distinction is the want of an areola l)efore the beaks. 



[Dr. Stimpson remarks : " I have found the differences between 

 this and tlie preceding species, mentioned by Dr. Gould, to be in- 

 constant." There is much doubt in my own mind also in regard 

 to its title to a separate name, as I have seen no extended series 

 for comparison. The shell figured in Sowerby's Thesaurus is widely 

 different from this, and is probably a South American species. 



Family TELLINID^, Lateeille. 



Not more than two cardinal teeth on the same valve ; a lateral 

 tooth each side when not obsolete ; ligament on the shorter end ; 

 pallial sinus very large ; animal with long slender separate siphons ; 

 mantle open. 



Oemis MACOMA, Leach. 1819. 



Shell equivalve, sul)-ovate, compressed, rounded anteriorly, sub- 

 rostrate posteriorly, slightly gaping at ends, with posterior sub-mar- 

 ginal flexure ; hinge with two small cardinal teeth in each valve ; 

 pallial impression with a deep sinus. Animal with one simple 

 fringe on each side. 



Macoma fusca. ' 



EiG. 42. 



Shell compressed, ovate-orbicular, sub-equipartite, rounded before and some- 

 what pointed behind; white, covered with a dusky epidermis; teeth, two in 

 each valve, the largest of which is grooved. 



Lister, t. 405, fig. 250. 



Psammohia fusca, Say, Jouin. Acad. N;it So. v 220 (182G). 



SamjuinoJariafasca, Conrad, Aiiier. Mar. Conch. 34, pi. 7, fig. 1 (1831).— Stimpson, Sh. 

 of New Eng. 20 ; Inv. Gr. Man. 2d ed. 21. —Gould, Inv. Mass. 1st cd. 66. -De 

 Kay, Nat Hist. N. Y. 212, pi. 32, fig. 304. — Mighels, Bost. Journ. N. H. iv. 317. 



Tellinafusm, Phil. Abbild. t. 3, fig. 3. 



Tellina inconspicua ? Sowerby, Zool. Journ. iv. 359. — Gray, Zool. Beech. Voy. 153, pi. 

 41, fig. 6. — Hanley, in Sowerby, Thes. Conch. 317, pi. 59, fig. 1:20. 



Tellina Gronlundlca, Beck, see Lyell, Tr. Geol. Soc. Lond. 1841, vi. 137, pi. 16, fig. 8. 



