440 A, E. Verrill—Mollusea of the New England Coast. 
two-thirds the length of the shell; the ligamental area is narrow-lan- 
ceolate, becoming long and narrow posteriorly ; its surface has only 
faint lines of growth, but its margins are clearly defined. The pos- 
terior margin descends obliquely, or with a slight incurvature, and 
then expands in a rounded curve. The ventral margin is gently 
convex, except where slightly indented by the byssal sinus. The 
anterior end is very short and narrow, ending superiorly in a small, 
obtuse angle. The inner margin is simple and plain, without any 
crenulations. The hinge-margin is thin and the teeth are small and 
rather inconspicuous; the posterior ones are eight or nine in number, 
in the form of very oblique, slightly raised ridges or folds, the two 
or three most posterior becoming less oblique and more conspicuous ; 
the short anterior portion bears about six small but prominent teeth, 
which stand nearly transverse to the margin. 
Length, 12™™; height, 7™"; thickness, 5™™. 
Station 2,226, in 2,021 fathoms, N. lat. 37°, W. long. 71° 54’; seven 
living specimens (No. 44,501). 
This species is much more elongated and more expanded poste- 
riorly than any form of A. pectunculoides, and the beaks are more 
prominent and nearer the anterior end. It is a much larger species. 
Limopsis aurita ? Jeffreys. 
? Arca aurita Brocchi, Conch. foss. Subap., ii, p. 485, pl. 11, fig. 9, (t. Jeffreys.) 
Limopsis aurita Jeffreys, British Conch., ii, p. 161, pl. 4, fig. 3; vol. v, pl. 30, fig. 1. 
Shell large for the genus, compressed, very oblique, somewhat 
rbhomboidal, with rounded corners, and the posterior ventral margin 
much produced and broadly rounded. The umbos are not promi- 
nent; the beaks are small, acute and curve directly inward. The 
dorsal margin is nearly straight, with rounded ends, and is much 
shorter than either of the other sides, its length being less than one- 
fourth the circumference of the shell. The ligament-area is very 
narrow and long, extending nearly the whole length of the dorsal 
margin, The cartilage is rather small and triangular. The hinge- 
plate is not very broad, considerably curved within, very narrow, 
and destitute of teeth at the center, opposite the cartilage-pit. It 
expands regularly and about equally on each side, and bears about 
six moderately stout, somewhat oblique, rounded teeth on the poste- 
rior side, and six or seven thinner, closer, and more transverse teeth 
on the anterior side, the two outer ones becoming more distant and 
much more oblique than the rest. The posterior margin is nearly 
straight for the greater part of its length, and the anterior margin is 
