PLIOCENE AND PLEISTOCENE FOSSILS FROM ALASKA. 



33 



posterior end more attenuated, rounded. 

 Height, 20 millimeters; length, about 24 

 miUiineters; diameter, 6 mOlimeters; but the 

 fragments available indicate that it may 

 attain double the above dimensions. 



Station 7623. Pliocene. From submarme 

 beach, 30 feet below sea level, half a mUe 

 northwest of Nome. Collected by E. M. 

 KincUe and P. S. Smith, 1908. U. S. Nat. 

 Mus. catalogue No. 324308. 



Astarte (Gonilia?) diversa Dall, n. sp. 



Plate V, figure 6. 



Shell small, rounded triangular, with promi- 

 nent prosocoelous pointed beaks; nearly equi- 

 lateral, the anterior end slightly shorter ; lunule 

 lanceolate, deeply impressed, concentrically 

 striated, bounded by a sharp angular keel; 

 escutcheon narrow, elongated, obscure; umbo- 

 nal angle about 90°, dorsal slopes straight, 

 ends and base evenly rounded; sculpture 

 divaricate, some specimens with narrow ribs 

 with the apex central and the interspaces 

 equal, the- ribs becoming wider and more 

 irregular toward the ends of the shell, others 

 with few broad divaricate ribs tending to 

 obsolescence in the middle of the disk, and 

 still others having broad, low ribs irregularly 

 broken up into flatfish nodules distributed 

 divaricately but more or less irregularly; 

 cardinal teeth short, narrow, two in the left 

 and one in the right valve; ligament short; 

 margin of the left valve, under the escutcheon, 

 grooved; cavity of the valve extending under 

 the hinge, adductor scars impressed, internal 

 margins of the valves smooth. Height, 15 

 millimeters; length, 18 millimeters; diameter, 

 8 millimeters; but reaching a larger size as 

 indicated by fragments. 



Station 7623 (1). Pliocene. Half a mile 

 northwest of Nome, from submarine beach 30 

 feet below the level of the sea. Collected by 

 E. M. Kindle and P. S. Smith, 1908. U. S. 

 Nat. Mus. catalogue No. 324309. 



This is a remarkable species. The typical 

 Gonilia (bipartita Philippi, as Lucina) is a small 

 Mediterranean shell with a crenulate inner 

 margin and obsolete lunule. Otherwise the 

 only systematic difference is of size. The 

 current descriptions of the original Gonilia are 

 in error in giving it three cardinal teeth in each 

 valve and stating that it has no epidermis. 



The latter feature is due to the fact that the 

 specimens dredged have been decorticated 

 single valves. As there was an earlier Astarte 

 hipartita of Sowerby when the Mediterranean 

 species was assigned to the genus, Philippi's 

 specific name could not be retained, and in 1903 

 I proposed as a substitute the name calliglypta. 

 The present species may, however, be more 

 nearly related to the Pacific Eictocyma than to 

 the Mediterranean Gonilia. 



Venericardia nuwokensis Dall, n. sp. 



Plate V, figure 14. 



Shell small, rotund, moderately inflated, 

 with slightty prominent beaks, dorsal angle 

 about 85°; sculpture of about 20 radiating ribs 

 with somewhat narrower channeled inter- 

 spaces, crossed by rather regularly spaced 

 low threads which swell into nodules on the 

 back of the ribs at their intersections; base 

 semicircular, internally crenulate in harmony 

 with the external sculpture; hinge normal, 

 teeth short and very strong for the size of the 

 shell. Height, 13 millimeters; length, 11 milli- 

 meters; diameter, 9 millimeters. 



Station 7230. Pliocene. Carter Creek. 

 CoUected by E. de K. Leffingwell, 1912. U. S. 

 Nat. Mus. catalogue No. 324310. 



Macoma middendorffii DaU. 



Plate VI, figures 11, 13. 



This peculiar species seems rather charac- 

 teristic of the Pliocene at Nome, although in the 

 Recent fauna it is more southern in its general 

 distribution, not having been found living 

 north of Bering Strait. It has been obtained 

 at stations 5074, 5077, 5078, 7619, 7621, and 



7622. 



Cyrtodaria camdenensis Dall, n. sp. 



Plate V, figure 7. 



Shell of moderate size, nearly eqtiilateral, 

 eqmvalve, gaping at both ends; the umbones 

 subcentral, inconspicuous, the anterior end 

 shghtly longer; valves thick, with an unsculp- 

 tured surface, more or less marked by concen- 

 tric incremental lines; dorsal and ventral 

 margins nearly parallel, anterior end rounded, 

 posterior end subtruncate, rounded above and 

 below; ligament strong and prominent; adduc- 

 tor scars small, palhal line distinct, entire, with 

 a small round scar at the ventral anterior end 



