BRANCHIURA FROM LAKE TANGANYIKA. 269 



ra.tlier large, roughly pear-shaped and armed with small spines. 

 No accessory processes are present between the bases of the 

 maxillipeds. Flagella present on the first two pairs of swimming- 

 legs. In the male, vesicula seminalis present on the third leg, 

 copulatory peg and accessory cushion on the fourth. In the 

 female, basal segment of fourth leg produced postero-laterally 

 into pointed lobe. Colour (in spirit) light brown, the testes 

 covered above by large in-egular blotches of dark brown. 

 Dimensions as follows : — 



Adult male (largest specimen). Adult female (largest specimen). 



mm. mm. 



Total length 7-3 Total length ..11-6 



Length of carapace ... 4"1 Length of carapace ... 6*2 



Breadth of carapace... 4"3 Breadth of carapace... 6" 7 



Remarks. — The most striking characteristic of this species is 

 the unusually deep antero-lateral depression or sinus, which 

 gives occasion for the specific name. This feature does not 

 occur in any other of the African species — a fact which naturally 

 suggests that excessive shrinkage might be the sole cause. Such 

 an explanation is obviously impossible in this case. The spe- 

 cimens were all of them taken from a single fish, in association 

 with A. siriatus, but the species were not distinguished on the 

 spot, and all the specimens were treated alike and were brought 

 home in the same bottle. On examination, the deep antero- 

 lateral incision first afforded a palpable distinction between the 

 forms, which proved to be specifically different to a marked 

 degree. Another important feature in which this type diflfers 

 from the other African species, and indeed from the great 

 majority of the known species, is the complete absence of 

 accessory spines or processes behind both the antennules and 

 maxillipeds. 



Occurrence. — Rumonge, 16/2/05. From mouth and surface of 

 body of large specimen oi Auchenoglanis occidentalism var. tangani- 

 canus. Ten males and thirteen females, some ovigerous. These 

 were associated with a large number of specimens of Argulus 

 striatus. 



Argulus rubropunctatus, sp. n. (PI. XLI. figs. 3-5 ; 

 PI. XLIII. figs. 19, 20.) 



Description. — Carapace in the male orbicular, slightly broader 

 than long; in the female elliptical, slightly longer than broad. 

 Antero-lateral depressions slight. Posterior lobes broad and 

 rounded, covering bases of all but fourth swimming-legs, and 

 separated by a broad sinus about one-fifth the length of the 

 carapace. The edge of the carapace below is well armed with 

 small spines, which extend into the region of the swimming-legs. 

 Abdomen in the male nearly two and a half times as long as 

 broad, about three-sevenths entire- length of body ; posterior 



