244 HOLMES 



Avith a small dorsal spine at the anterior end. Second segment tumid 

 posteriorly, but narrowed in front of the gnathopods ; the second, third, 

 and fourth segments are more or less elevated at the two ends and de- 

 crease successively in length. Second gnathopods inserted behind the 

 middle of the segment, the basal joint very short and broad, widened 

 distally, and somewhat produced at the antero-distal angle, the anterior 

 margin roughened from the small prominences similar to those occurring 

 on the surface of the body and the other appendages ; merus produced 

 and rounded below ; carpus very short ; hand oblong, curved backward, 

 much longer than all the preceding segments ; palm concave, devoid of 

 a spine near the upper end but furnished with a large spine near the 

 lower extremity, which is separated by a deep narrow sinus from a tooth 

 below. Gills broadly oval to nearly round. Posterior peraeopods with 

 the palm occupying over four fifths of the posterior margin of the hand, 

 and defined above with a prominence bearing a pair of serrated spines ; 

 carpus with an oblique row of tubercles on the lower edge. Penes 

 median. Abdominal appendages clearly two-jointed. 



Length, 19 mm. 



The young males differ considerably in appearance from the adults ; 

 the antennae are nearly equal in length and thickness and the peduncle 

 of the iirst pair relatively less stout ; the iirst two segments of the thorax 

 are much less elongated, and the second gnathopods are joined near the 

 middle or even in front of the middle of the segment ; the hand of the 

 second gnathopods is oval in outline and convex instead of concave 

 posteriorly, and is furnished with a prominent tooth at the upper end of 

 the palm, near which is a small spine on the surface of the hand ; near 

 the lower end of the palm are two small teeth. In somewhat larger 

 specimens the hand is more elongated, the palm straighter, the teeth near 

 the lower end of the palm more prominent ; the upper tooth becomes 

 more reduced and persists in quite large specimens, but finally disappears. 

 The different insertion of the second gnathopods in the adult males is 

 brought about by the elongation of the anterior portion of the second 

 thoracic segment. 



In the female the first antennae are but little longer and scarcely stouter 

 than the second pair, and the first two segments of the peduncle of the 

 first pair are not enlarged ; the first segment of the thorax is about as 

 deep as long ; the second gnathopods are inserted in front of the middle 

 of the second thoracic segment, the anterior portion of the segment not 

 being prolonged as it is in the adult male. 



The roughness of the body is subject to considerable variation. Some 

 specimens are nearly smooth ; others, and especially the females, are fur- 

 nished with short spines on the posterior segments. 



