434 PROCEEDINGS OF THE NATIONAL MUSEUM vol.83 



three joints taken together are longer than the basis; last two joints 

 taken together not quite two-thirds as long as the carpus ; the dactyl 

 longer than propodus. There are no rudimentary exopodites on 

 the third and fourth pereiopods. 



The uropods (fig. 37, c) are long and slender. The peduncle is 

 longer than the last two abdominal somites taken together. Its in- 

 ner margin is sparsely spined; spines somewhat variable in size. 

 The endopod is about as long as the telson; the exopod somewhat 

 longer. The three joints of the endopod vary but slightly in length, 

 and carry isolated spines on their inner margins. 



The integument is roughened practically throughout with tiny 

 chitinous processes or projections. These vary in size, at times even 

 assuming the character of fine, small teeth, as on the posterior re- 

 gion of the carapace and also on the sides of the free thoracic and 

 abdominal somites, as well as on the outer surface of the proximal 

 portions of the pereiopods. 



Length. — About 9 mm. 



Male in nupticd dress (fig. 37, /-A). — The differences in the body 

 form and in the development of the extremities usually found be- 

 tween the males and females within the genus occur here also; the 

 three lenses are more distinct on the ocular lobe, the setae in the 

 subrostral notch are stronger and more numerous, and the area about 

 the subrostral angle is clearly denticulate. On the other hand, the 

 row of denticles on the margin of the carapace behind keel no. 2 is 

 lacking. The keels found on the carapace of the female are present 

 but are not nearly so high or so strongly developed, nor are the areas 

 between them so deeply e:xcavated. Their placement is also some- 

 what different: Angle no. 2 is moved farther backward and sub- 

 stantially nearer the median line than in the female ; keel no. 1 even- 

 tually disappears anteriorly without reaching the edge of the cara- 

 pace; keel no. 5 is very short. It eventually disappears toward the 

 median line and here merges with an indistinct longitudinal keel, 

 which runs from about the mid length of the frontal lobe to the 

 point of juncture with keel no. 5 in the median line of the carapace. 

 From the forwardly turned branch of keel no. 4 and, in fact, at about 

 the point where the turn is completed, originates another keel that 

 runs to the posterior edge of the carapace. This keel is entirely 

 absent in the female. It corresponds with the forward-running 

 branch of keel no. 4, of the "lateral line", which so frequently is 

 found in the male in the family Diastylidae. 



The difference in length between preanal and postanal portions 

 of the telson (fig. 37, /) is not so pronounced as in the female, while 

 the telson is proportionately longer and slenderer. It attains the 

 length of the penultimate abdominal somite and is, like it, clearly 



