1885.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 183 



Hymenopenceus modestiis, sp. uov. 



Kearly the whole surface of the carapax is more or less pubesceut, bat 

 the pubescence is very inconspicuous except in front of the cervical 

 sulcus, where it is especially noticeable either side of the dorsal carina 

 and along the margins of the orbits. The surface of the pleou is almost 

 entirely naked and glabrous. The carapax is considerably compressed, 

 slightly narrowed in front, and the dorsum is rounded and without a 

 carina back of the cervical sulcus, while in front there is a low dorsal 

 crest terminating in, a small and nearly horizontal rostrum which is 

 slightly more than a fourth as long as the rest of the carapax, does not 

 reach as far forward as the eyes, terminates in an acute tip, and is armed 

 above with three small teeth in front of the orbit and with four others 

 in the dorsal crest back of the orbit, while beneath it is ciliated and un- 

 armed. There is a shallow hepatic sulcus and the cervical sulcus is 

 conspicuous, reaches nearly to the middle of the dorsum, and is bordered 

 posteriorly by a sharp and slightly carinated margin. There is no per- 

 ceptible supraorbital tooth, the antennal spine is small and less con- 

 spicuous than the one a little back cf and very slightly above it, and 

 there is a small branchiostegial spine a little way back from the evenly 

 rounded anterolateral angle. 



The eyes including the stalks are about a fourth as long as the cara- 

 pax excluding the rostrum, and the eyes themselves are black, rather 

 small, and approximately hemispherical, but considerablv compressed 

 vertically. 



The peduncle of the antenna is nearly as long as the antennal scale : 

 the proximal segment reaches considerably beyond the eyes and the 

 outer margin is armed with a median tooth and distal spine; the sec- 

 ond segment is approximately three-fourths as long as the proximal, 

 somewhat triquetral Jj^nd hairy; and the distal segment is less than half 

 as long as the second and subcylindrical. The flagella are nearly cylin- 

 drical, subequal in length, and scarcely as long as the carapax includ- 

 ing the rostrum : the superior is slightly but suddenly narrowed about 

 a fourth of its length from the base, and beyond this point is exceed- 

 ingly slender ; and the inferior is very much stouter than the superior 

 and sparsely hairy. 



The antennal scale is a little less than three-fourths as long ^ the 

 carapax excluding the rostrum, slightly more than a fourth as broad 

 jas long, and uniformly tapered from the base to the very narrow but 

 pounded tip, which reaches considerably beyond the peduncle of the 

 antennula. 



The distal segment of the mandibular palpus is approximately as 

 long as the proximal but very narrow, being about four times as long 

 as broad. The second gnathopods reach beyond the tips of the anten- 

 nal scales by nearly the full length of the dactyli. 



The first perieopods are strongly compressed and reach beyond the 

 bases of the antennal scales by about the length of the dactyli ; the 



