168 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. [1885. 



of a conspicuous regularly semicircular suture limiting the hepatic 

 region below and behind. The inferior edge of the rostrum is sharp 

 and slightly roughened but not distinctly dentate. From the sides of 

 the rostrum two low rounded carinie extend back a little way upon the 

 gastric region, and are each armed with two spines somewhat smaller 

 than the lateral spines of the rostrum, while much farther back, upon 

 the posterior margin of the cervical suture, there is a pair of similar 

 subdorsal spines much nearer together. The anterior margin projects 

 either side in a great vertically compressed dentiform spine reaching in 

 an acute point as far forward as the eyes, and recalling similar spines in 

 some of the Crangonidse. Just back of the base of the antennal spine 

 there is a small spine on the hepatic region, and between this and the 

 posterior subdorsal spine of the gastric region, and back of the orbit, 

 there is a similar spine. The carapax is everywhere roughened with 

 minute tubercles between which the surlace is beset with very short 

 hairs. 



The eyes, though not quite as large, are nearly like those of Nephrops 

 Rorvegicus, being vertically compressed, rpuiform, and black. 



The antennulse are like those of Nephrops Norvegicus. The general 

 form and proportions of the bodies of the segments of the peduncle of 

 the antennae are almost exactly as in Nephrops Norvegicus, but the second 

 segment is evenly convex externally and without any trace of a tooth or 

 spine at the base of the very small antennal scale, which is very little 

 more than half as long as the fourth segment, about half as wide as 

 long, oblong-ovate, with a minute tooth at the tip and with the inner 

 edge ciliated. The flagellum is considerably longer than the body of 

 the animal and very nearly as in Nephrops Norvegicus. 



The oral appendages agree very closely in every detail with those of 

 Nephrops Norvegicus, except that there is a well-developed podobran- 

 chia, fully as large as in Homarus Americanus, at the base of the first 

 gnathopod. 



In the single specimen seen the right cheliped is in process of repro- 

 duction and very rudimentary. The left cheliped agrees in general 

 form very closely with the more slender of the chelipeds of Nephrops 

 Norvegicus : the inferior and superior edges of the merus, though rough- 

 ened with somewhat spiniform granules, bear only one real spine each 

 and that at the distal end ; the spines of the carpus are slightly fewer, 

 but arranged nearly as in Nephrops Norvegicus ; the chela itself is very 

 slightly broader than in Nephrops Norvegicus, the spines of the carinae 

 are a little less prominent, though the carinae are spinulose or minutely 

 tuberculose nearly to the tips of the digits, and the spaces between the 

 carin.TB are thickly tuberculose and not pubescent. The remaining pe- 

 raeopods are very nearly as in Nephrops Norvegicus. 



The pleon is in general very much like that of Nephrops Norvegicus, 

 but the whole dorsum is pubescent, and the second, third, and fourth 

 somites have only an inconspicuous, transverse, dorsally interrupted 



