Shell white, covered with a papery, pale olive-gray periostracum; apex subcentral, minute, hardly prominent; sculpture of rather sparse and feeble radial threads, incremental lines, and an almost microscopic sagrination without definite pattern, but chiefly concentric and occasionally microscopically pustular. Interior white, smooth, the muscular horseshoe-shaped impression very broad and high up in the shell, its anterior end directed in a contrary sense to the apex of the shell.
Length from anterior end to apex, 5.7; of whole shell, 12; breadth, 8; height, 4.7 mm.
Station 6052, San Juan Harbor, Porto Rico, in 310 fathoms.

Shell large for family (reaching 12 mm), moderately thick, white, inflated, ovately conical, high (SH/ SL = 0.41-0.46). Apex anterior of center (P/SL = 0.44-0.46). Protoconch forming apex, 250 µm in length, with posterior ventral margin embedded in posterior slope of shell. Protoconch sculpture of raised cords forming reticulate pattern aligned longitudinally in rows. Surface within reticulations finely pitted. Teleoconch sculpture of weak, irregular growth lines, and feeble radial cords and intervening threads, most clearly discerned along posterior slope. Anterior and posterior slope weakly, evenly convex. Aperture nearly planar, weakly ovate, narrower anteriorly. Shell edge thick. Periostracum thin, strongly hirsute but hairs confined to shell margin, worn or absent nearer to apex. Periostracal hairs follow radial cords and threads.
External anatomy : Animals lacking pigmented eyes. Penis emerging from right cephalic tentacle, Y-shaped, with inner, shorter branch comprising copulatory organ and longer, flatter, outer branch forming penial fold .Pseudoplicatid gill on right side dorsal to oral lappet. Pair of posterior epipodial tentacles.
Radula : Rachidian teeth with broad attachment area, broad, thickened anterior edge without discernible cusps; first lateral teeth with 1-3 cusps, second lateral teeth with 5 cusps, third lateral teeth with single cusp. Pluricuspid teeth broad, with large main cusp and single, inner and outer secondary cusps. Marginal teeth similar in size.

Dall & Simpson (1901) described this species in the genus Cocculina Dall, 1882, commenting on its conchological similarities to C. rathbuni, and noted its lack of eyes and the presence of a large penis projecting from the right cephalic tentacle, a pseudoplicatid gill, and long, paired, epipodial tentacles. McLean & Harasewych (1995:17) transferred C. portoricensis to the genus Coccocrater Haszprunar, 1987, recognizing that the combination of anatomical features and the absence of a hirsute periostracum were diagnostic of that genus.
The newly collected and well preserved specimens of C. portoricensis clearly have a hirsute periostracum, at least near the shell edge. However, these periostracal hairs are worn and absent over most of the shell surface, which closely resembles that of the holotype of C portoricensis. The periostracum of C. portoricensis is similar to but has longer hairs than does Coccopigya mikkelsenae McLean & Harasewych, 1995. The radulae of these two species are also very similar, although C. mikkelsenae has rachidian teeth with a thickened anterior edge and one or more distinct cusps (see McLean & Harasewych 1995:fig. 45). The penis of C. portoricensis is bifid, while that of C. mikkelsenae consists of a single, tapering lobe. Despite the similarity to Coccopigya mikkelsenae, we provisionally retain C. portoricensis in Coccocrater.

This species was known from a unique holotype taken in 566 m off San Juan Harbor, Puerto Rico, until Diaz & Puyana (1994:113) reported it from an area slightly to the north of the present record (Diaz & Puyana 1994:fig. 15, sector 2), at depths ranging from 40 to 600 m. The specimens we illustrate came from a depth of 272-310 m, substantially shallower than the holotype. Since cocculinids inhabit primarily bathyal depths, the published 40 m record will require confirmation.