296 Transactions of the Society. 



F ureal rami symmetrical in both sexes. Eostral processes dis- 

 tinct but small. First pair of antennas in the female reaching 

 considerably beyond the 1'urca. In the male the penultimate 

 joint of the prehensile antenna bears a short hook and a very 

 narrow hyaline membrane (plate XII. fig. 30). The 14th, 15th, 

 and 16th joints each have a short, strong spine (plate XIII. 

 fig. 34). 



The fifth foot of the female has the endopoclite one-jointeel and 

 half as long as the first joint of the exopodite (plate XIII. fig. 33) ; 

 the third joint of the latter is distinct and well developed, bearing 

 a short spine and a seta which reaches nearly the end of the 

 spinous process. 



In the right foot of the male (plate XII. fig. 32) the second 

 basal joint bears two minute cuticular processes ; the endopodite 

 is equal to the first joint of the exopodite ; the second joint of the 

 latter has no cuticular processes ; and the lateral spine is very 

 short and near the end of the joint. In the left leg the basal 

 joint has no cuticular processes ; the endopodite is longer than 

 the first joint of the exopodite ; the second joint of the latter is 

 prolonged into a short, blunt process. The third joint is repre- 

 sented by a short seta. 



Measurements : — 



Sagittal 



,, with furca 

 Thorax 

 Abdomen 



,, 1st segment 



„ 2nd „ 



,, 3rd „ 



., 4th „ 



,, 5th „ 

 Furca 

 Left antenna 



A few specimens of the species here described were found in a 

 pool at Oued Tindja in company with Popjpella guemci. The 

 resemblance between them and D. drieschi Poppe and Airazek on 

 the one hand and D. steinclachneri Eichard on the other is so close 

 that I have been in much doubt as to whether the species should 



EXPLANATION OF PLATE XIII. 



Fig. 33. — Diaptomus numidicus. 5th leg of female, x 260. 

 „ 34. — Ditto. Part of right antenna of male, x 260. 

 ,, 35. — Diaptomus cyaneus sp. n. Female, x 37. 

 „ 36. — Ditto. Abdomen of female, x 65. 

 „ 37.— Ditto. 5th legs of male, x 98. 

 ,, 38.— Ditto. 5th leg of female, x 150. 



