MUSEUM OF COMPARATIVE ZOOLOGY, 299 
Yoldia sapotilla (GouL») Srrwr. 
Over fifty living specimens, Station 344, south of Martha's Vineyard, in 129 
fathoms, Six living and three dead, Station 345, south of Martha's Vineyard, 
in 71 fathoms. Four living and two valves, Station 346, south of Martha's 
Vineyard, in 44 fathoms. 
A common species found by the U. S. F. C. from the Bay of Fundy and 
west of St. Peter’s Bank to off Martha’s Vineyard, in 44 to 1,054 fathoms ; not 
living in less than 8 fathoms, or below 428 fathoms, Also recorded by Mr. 
Whiteaves from the Gulf of St. Lawrence, and by Professor Packard from 
Labrador. 
Yoldia lucida Lovén. 
Leda lucida Jeffreys, Brit. Conch., V. p. 173, pl. 100, fig. 1, 1869. 
Yoldia obesa Gould, Invert. Mass, Binney’s ed., p. 155, fig. 463, 1870. 
Verrill, Invert. Anim. Vineyard Sd., p. 896, 1874. 
Portlandia lucida Sars, Moll. Reg. Arct. Norveg., p. 37, pl. 4, figs. 8 a, 8 b, 1878. 
Leda lucida Jeffreys, Proc. Zoöl. Soc., London, p. 578, 1879. 
Yoldia lucida Verrill, Trans. Conn, Acad., V. pl. 44, fig. 1, 1882. 
One living specimen, Station 305, east of George's Bank, in 810 fathoms. 
A small species found in considerable numbers by the U. S. F. C. from the 
Bay of Fundy and northwest of Flemish Cap to off Cape Hatteras, N. O., in 22 
to 2,620 fathoms. 
Recorded by Mr. Whiteaves from the Gulf of St. Lawrence. 
Yoldia callista, sp. nov. 
Plate I, Figs. 9 and 10, 
One living specimen, Station 321, off Charleston, S. C., in 233 fathoms. 
This is a very small species, with a smooth, shining surface, covered with 
very fine microscopic lines of growth, It is narrow, nearly regularly ovate in 
outline, with small beaks, curved well forward, and situated at about the ante- 
rior third, Exteriorly the shell resembles a minute Callista. The anterior 
dorsal margin is somewhat concave, the posterior decidedly convex ; while the 
ends are narrowed and nearly evenly rounded to meet the regularly curved 
ventral margin. Epidermis wanting. The interior has also a very shining: 
surface with plain margins. The hinge margin is rather wide and thin, with 
six distinct well-separated teeth before and nine behind the beak. Cartilage 
pit minute, triangular, situated directly below the beak. 
Length, 2.5 mm.; height, about 2 mm. 
This species bears considerable resemblance to the young of Y. regularis, 
described by Professor Verrill (Trans. Conn, Acad., VI. p. 228, 1884), but the 
latter is very much broader and more oval in outline, with broadly rounded 
ends and the dorsal margins evenly convex. The most striking differences are 
