DALL: MOLLUSCA AND BRACHIOPODA. 399 
bear a superficial similarity, and recently M. Cossmann has expressed the same 
opinion. There is a pretty gradual shading off from the Hocene type to that of 
the recent species, but the inequilateral shell, the V-shaped ligament, and the 
general aspect forbid us to refer these little species to the typical Barbatia, and 
it will therefore be convenient to retain Conrad’s name. 
Arca (Cucullaria) endemica Dat1, n. sp. 
Plate 17, figure 8. 
Shell small, thin, brownish, inequilateral, equivalve, moderately inflated ; beaks 
small, pointed, slightly prosogyrate, situated at about the anterior third, separated 
by a long, narrow, flat, lozenge-shaped area on which the ligament, which is wholly 
opisthodetic, forms a long, very acute V; surface dull, minutely concentrically 
imbricate, radiately sculptured with numerous close, very fine rounded threads which 
become wider and flatter distally ; periostracum fibrous, dehiscent; anterior end 
attenuated, short, pointed ; posterior end broad, rounded, compressed ; a shallow 
radial constriction extending basally from the beaks; base oblique, with a narrow 
gape for the byssus at the extremity of the constriction; interior porcellanous, white, 
the scars evident; hinge rectilinear, anterior teeth six, vertical, separated by a gap 
from the narrow oblique series of eight posterior teeth; margin forming an angle 
at each end of the hinge plate. Lon. of shell, 11.5; of beaks behind the anterior 
end, 3.0; max alt., 7.0; diam., 4.5 mm. 
U. S. 8. “Albatross,” station 4721, Pacific Ocean, in 8. Lat. 8° 07’ and 
W. Lon. 104° 10’, in 2084 fathoms, globigerina ooze, bottom temperature about 
35° F. U.S. N. Mus. 110,578. Also at station 4685, in S. Lat. 21° 36’ 
and W. Lon. 94° 56’, in 2205 fathoms, radiolarian ooze, bottom temperature 
35°.3 F. 
This is very close to Arca (Cucullaria) pteroéssa KE. A. Smith, of the Mid 
North Pacific, but has a coarser radial sculpture and less numerous teeth. 
GLYCYMERINAE. 
GLYCYMERIES Da Costa. 
Glycymerts Da Costa, Brit. Conch., 1778, p. 170; type, Arca glycymeris Linné. 
Pectunculus Lamarck, Prodrome, 1799, p. 87; not of Da Costa et al. 
Pseudaxinea Monterosato, Nota int. Pectunculus dei mari d’Europa, 1892; type, 
P. violauscens Lamarck. 
Glycymeris multicostatus Sowzrsy. 
Pectunculus multicostatus Sowerby, P. Z. S. Lond., 1832, p. 195; Reeve, Conch. Icon., 
1, Pectunculus, pl. 5, fig. 26. 
Bay of Guayaquil, Cuming. U.S.S. “Albatross,” station 3368, near Cocos 
Island, in 66 fathoms, rocky bottom, temperature 58°.4 F. U.S. N. Mus. 
122,877. 
The single valve obtained as above has all the aspect of the specimens of G. 
