588 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [86] 
the middle of the ventral margin, curving a little backward ; the hinder- 
most terminates about midway between the former and the end of the - 
rostrum, curving strongly backward ; the most anterior one ends about 
‘midway between the middle one and the anterior end of the shell; mid- 
way between this and the middle one, there is a smaller secondary rib. 
These three primary ribs are strongly elevated, not very broad, with the 
summit rather thin, finely notched by the concentric linés of growth; 
the most posterior rib is the largest and highest, and projects most at 
the margin. Between these ribs the spaces are wide and strongly 
concave, marked by numerous and regular lines of growth. On the 
anterior end of the shell there are two or three smaller radiating ribs, 
which are separated by intervals about equal to their own breadth, and 
give the margin a slightly crenulated appearance. The rostrum is nar- 
row, strongly compressed, with both the dorsal and ventral outline 
concave. Twosmall ridges run from the beak to the tip of the rostrum, 
separated by a very narrow, flattened area. The right valve has two 
well-marked lateral teeth, the posterior one considerably longer and 
larger than the anterior; between these there is a small, ovate cartilage- 
pit. The inner surface of the valves shows deeply indented grooves cor- 
responding to the primary external ribs. Color, opaque white. Epider- 
mis indistinct. 
Length of the largest specimen, 6™; height, 4™™; thickness, 4™™. 
Four living and one dead specimens (No. 35,362) were found at 
station 2,108. 
This species bears considerable resemblance to N. ornatissima D’Orb., 
but the ribs are less numerous, more curved, and the primary ones are 
much larger and more widely separated, and the shell is less convex. 
There is no other similar species known from the Atlantic coast. 
Clidiophora trilineata (Say) Carpenter. 
B. range, 14 to 15 fathoms.t 
Pandora, sp. 
B. range, 14 to 48 fathoms.t 
Spisula solidissima (Dillwyn) Gray. 
B. range, 14 to 15 fathoms.t 
Macha strigillata (Linné), var. (?) 
B. range, 15 fathoms.t 
Tellina alternata Say. 
B. range, 15 fathoms.t 
Tellina lintea Conrad. 
B. range, 14 to 15 fathoms.t 
Tellina iris Say. 
B. range, 15 fathoms.* 
Anyulus tener (Say) Adams. 
B. range, 14 to 15 fathoms ;* 48 fathoms.t 
