302 A. FE. Verrill—Marine Fauna off New England coast. 
posteriorly ; a small portion, near the tip of the posterior end is 
covered only by slight ribs. e surface between the ribs is 
finely granulated. When the thin superficial layer is removed 
the surface is pearly. The umbos are prominent, strongly in- 
curved, nearly or quite in contact. The binge in the right valve 
consists of a small, slightly prominent lamella, ranning back asa 
low ridge, and separated from the margin of the shell anteriorly, 
and from the cartilage-lamina posteriorly, by a narrow groove ; 
the cartilage-pit is long, ranning forward under the beak as a 
a narrow furrow; it is bounded internally by a prominent 
lamella. Length, 86™; height, 29 ™™; breadth, 26™™. 
Stations 940, 949, 950: 69 to 130 fathoms. 
Three specimens, all dead, but one is very fresh. 
Mytilimeria flexuosa Verrill and Smith, sp. nov. 
Shell obliquely cordate, short, higher than long, very swollen, 
the anterior end rather shorter than the posterior; umbos very 
prominent, beaks much incurved, pointed and turned forward, 
with a small, deep concavity just under and in front of them. 
The outline and surface of the shel] is very flexuous, owing to 
the broad deep grooves and elevated ribs which divide the sur- 
face into several areas. The most prominent rib is very high 
and rounded, and runs from the beak to the extreme ventral 
margin, inclining somewhat forward; in front of this the ante- 
rior area is flattened with a wide shallow concave groove or 
undulation in the middle, and others less marked; the front 
edge is broadly rounded, slightly undulated below. The mid- 
le area is very elevated, and forms more than a third of the 
shell; it is flattened or slightly concave in the middle, and 
undulated by several faint broad ribs; it recedes posteriorly, — 
and a broad concave furrow separates it from the small poste- 
rior area, which is without ribs, and has a prominent rounded 
edge. The surface is finely granulated, lines of growth evident. 
The interior is pearly, angulated by a deep groove, correspond- 
ing to the largest external rib. The dorsal hinge-line is nearly 
straight posteriorly, and strongly incurved anteriorly, in the 
right valve it projects inward, but not in the left; in the right 
valve there is a small rounded tubercle, a little back of the . 
beak ; from below this a short rib-like process runs back below 
the deep, partially internal cartilage-pit, which extends forward 
and upward under the beak as a narrow furrow. Anterior 
muscular scar deep; posterior one larger ovate, less distinct; 
sinus smal]. Length, 25™"; height, 26™; breadth from side 
to side, 22™™. 
Station 947; 312 fathoms. One pair of fresh valves, dead. 
- This and the preceding were both taken by means of the 
“rake-dredge.” 
