DALL: MOLLUSCA AND BRACHIOPODA. 419 
This group differs from the typical Vesicomya chiefly by the possession of a 
distinct angular pallial sinus. The hinge and other characters in essentials are 
the same, but we may suppose, in the absence of any positive knowledge of the 
animal, that this indicates longer siphons than in such species as V. s¢earnsii, 
where they are known to be complete and papillose, longer than in Isocardia, but 
still quite short. 
Vesicomya (Callogonia) angulata Dat. 
Plate 6, figure 12. 
Callogonia angulata Dall, Proc. U. S. Nat. Mus., 1896, 18, p. 19. 
Shell elongate, moderately inflated, the surface as in the other species; the 
anterior end rounded, shorter; the posterior end produced, pointed ; ligament 
short, set in a groove; the posterior dorsal border marked by two obscure ridges 
radiating from the beak, the outer one of which terminates at the posterior extreme 
of the valve, angulating the margin; the epidermis is denser and lamellose in the 
interspaces between these ridges; lunule obscure; basal margin nearly straight, 
rounded up toward the ends; beaks low, anterior; interior white, with some radial 
striae; hinge narrow; right valve with two low cardinals coalescent above, and a 
third, higher, springing between them; pallial line distinct, with an angular, rather 
short sinus. Height, 35; length, 58; semidiameter, 10 mm. ; the vertical of the 
beaks, 18 mm. behind the posterior end of the shell. 
U.S. S. ‘ Albatross,’’ station 3392, in the Gulf of Panama, in 1270 fathoms, 
hard bottom, temperature 36°.4. U.S. N. Mus. 122,933. Also (fragments) at 
station 3360, in 1672 fathoms, sand, temperature 36°.4 F. 
A single right valve of this distinct species was collected as above, and differs 
from Vesicomya especially by its angular pallial sinus. 
(TELEODONTA) 
Tellinacea. 
Tellinidae. 
TWELLINA (L.) Lamarck. 
Arcopagia Leacu. 
PHYLLODINA Dat. 
Tellina (Phyllodina) fluctigera Da tt, n. sp. 
Shell solid, elongate-ovate, nearly equilateral, of a yellowish white color; 
beaks low and flattish; anterior dorsal slope gentle, straight; anterior end 
