MARINE MOLLUSCA OF THE UNITED STATES. 165 



6. A. lutea, Perkins. Fig. 418. 



Proc. Bost, Soc. Nat. Hist., xiii. 151, figure. 1869. 

 Shell gibbous, thick, subtrigonal, length and breadth nearly 

 equal ; beaks prominent, incurved, not meeting ; surface with 

 twenty or more concentric ridges; margin crenulated within. 

 Length 23, breadth 21 mill. 



Connecticut. 



Animal with light yellow mantle, edged with bright orange ; 

 foot bright orange,' striped longitudinally with yellow. Ovaries 

 full of bright orange ova in April. 



A somewhat doubtful species ; its form too close to that of 

 borealis. 



7. A. sulcata, Da Costa. Figs. 419, 420. 



{Venus.) Brit. Conch., 192. 1778. 

 Crassina Danmoniensis, Lamarck, Anim. s. Vert., edit. Deshayes, vi. 360. 

 Astarte undata, Gould, Invert. Mass., 80. 1841. 

 Astarte latisulca, Hanley, Desc. Cat. 87, t. 14, f. 35. 1843. 



Shell ovate-triangular, thick, somewhat compressed ; anterior 

 side somewhat shortest ; beaks in contact, obtuselj' pointed ; sur- 

 face with from ten to twenty concentric furrows and ridges, the 

 former wider than the latter. Epidermis dark brown. Hinge 

 margin crenulated. 



Length 31, height 25 mill. 



Neio England, northwards. 



, Doubtful Species. 



S. A. lunulata, Conrad, Foss. Tert. Form., 44, t. 21, f. 8. 

 A. bilunulata, Conr. Adams. Genera, ii. 484. 



This species is inserted in Stimpson's Check-List of Atlantic 

 Coast Shells, but I think it exceedingly improbable that it has 

 been correct^ identified with any living species. 



Genus GOTILDIA, C. B. Adams. 



1. G. mactracea, Linslejr. Fig. 421. 



{Astarte.) Gould, Am. Journ. Sci., 233. 1849. 

 Shell small, solid, trapezoidal or quadrant shaped, triangular 

 above, rounded below ; surface undulated by about fourteen con- 

 centric waves or ribs, with very minute radiating striae. Color 

 yellowish-green. 



Length and height 6 mill. 



Massachusetts to South Carolina. 



