650 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 41, 



Fig. 73.— Diastylis 

 abgentata, fe- 

 male, second 



LEG. 



denticles on its posterior margin, and the fifth somite has also a few 

 denticles posteriorly. 



The telson is about twice as long as the last somite, its sides about 

 parallel for half its length, then converging gradually. There are 

 about six pairs of lateral spines, the distal ones at 

 least as large as the terminal pair. 



In the peduncle of the antennules the second seg- 

 ment is not more than half the diameter of the first, 

 and the third is still more slender ; the third is shorter 

 than the first and about half as long again as the 

 second. None of the segments of the antennae are 

 elongated. 



The basis of the third maxillipeds is not expanded 

 or produced distally, and the ischium and merus are 

 narrow. 



The basis of the first legs is slender and has a row 

 of strong curved teeth on the distal part of its outer edge; it is a 

 little shorter than the distal segments together. The dactylus is 

 about three-fourths as long as the propodus and a little shorter than 

 the carpus. 



In the second legs the basis has a row of strong spiniform teeth 

 along its outer margin ; the ischium has a curved 

 spiniform tooth on its inner edge; the carpus is 

 longer by one-fourth than the distal segments 

 together. 



The posterior pairs of legs have the basis ser- 

 rated on the outer side. There are no exopods 

 on the third and fourth pairs. 



The peduncle of the uropods is not quite two 

 and a half times as long as the last somite; the 

 exopod is about two-tliirds as long as the pe- 

 duncle and extends beyond the terminal spine of 

 the endopod; the endopod has onl}^ one articula- 

 tion, about the middle of its length, the second 

 and third segments being completeh" coalesced, 

 and its short stout terminal spine is not defined at its base. The 

 peduncle bears spines on the distal part of its inner edge, and the 

 endopod has about seven spines internally. 

 Adult maZe.— Total length, 9.2 mm. 



Height of carapace less than half, its breadth about two-thirds, of 

 its length; seen from the side its dorsal outline is slightly arched, with 

 a distinct notch at the base of the pseudorostrum. There are a few 

 denticles above on the pseudorostrum and frontal lobe and an oblique 

 line running backwards on the side of the pseudorostrum. The 



Fig. 74.— DLA.STTLIS argen- 



TATA, FEMALE, LAST SO- 

 MITE, TELSON, AND UROPOD. 



