dU BIOLOGICAL SURVEY OF 



DIASTYLIDAE 



Ekdiastylis cornuifer spec. nov. (fig. 15) 



Female : The carapace seen from above is pentagonal, tlie 

 anterolateral corners marked by short spines, one on each 

 side and each followed by a second smaller spine. The lat- 

 eral margins of the pseudorostral lobes are divided approxi- 

 mately into thirds by two minute spines. A minute middorsal 

 spine occurs at the base of the eye-lobe and another near the 

 posterior margin of the carapace. Each of the pedigerous 

 segments and the first three pleon segments bears a pair of 

 small dorsal spines. The epimera of each of the pedigerous 

 segments bear two or three marginal spines. The fourth and 

 fifth pleon segments bear single midlateral spines and a pos- 

 terior flange. The peduncle of the uropod is about twice the 

 length of the sixth pleon segment and once and a half the 

 length of the exopod. The telson is broken. 



Male: The general appearance is similar to that of the 

 female. The spines at the anterolateral corners are closer 

 together and almost the same size. They are larger than in 

 the female. The lateral margins of the pseudorostral lobes 

 bear a varying number of spines on the middle half. The 

 posterior half of the inferior margin of the carapace bears 

 a row of spines. The spinulation of the pedigerous segments 

 and the pleon is the same as in the female, except that as 

 many as four spines may be present on the epimera. Two 

 pairs of partly developed pleopods are present. The telson 

 is slightly longer than the peduncle of the uropod and has 

 three lateral spines on the left side and four on the right. 

 The terminal portion is a little more than half the length of 

 the whole telson. The exopod is about two-thirds of the 

 length of the peduncle of the uropod. The endopod slightly 

 exceeds half the length of the peduncle, and the second joint 

 is three-fourths the length of the first. 



Length : 5 to 6 mm. in the immature examples. 



Type : Female, Crust. 1125 ; cotype, male. Crust. 1126 

 Boston Soc. Nat. Hist. ; paratype, immature female, B 171. 



Remarks: I have not yet seen any fully adult specimens 

 of this species. It belongs to the group comprising E. Jiexa- 



