1906.] CRUSTACEA OF THE THIRD TANGANYIKA EXPEDITION. 189 



the genus Caridina, Dr. de Man goes on to say — " P. sundaicus 

 Heller, with its varieties, does not seem to me to be the most 

 nearly allied to P. moorei as you suggest. Like Couti^re (Ann. 

 Sci. Nat. 8™^ ser. xii. p. 324), I think that P. superbus Heller 

 and P. ii'ompi de Man, especially the former, are the most closely 

 allied species. P. scabriculics Heller and P. alcocki ISTobili are 

 apparently also related. All these forms, however, are in a greater 

 or less degree different from your species. P. trompi, from Borneo, 

 is at once distinguished by the few and large eggs, by the shape 

 of the telson, the toothing of the fingei'S, &c. P. scabriculus differs 

 in the carapace, which is scabrous, in the rostral teeth, of which 

 six are set on the caiupace, and in other characters. P. alcocki 

 has the carpus of the second legs almost twice as long as the 

 merus, and little shorter than the chela. P. moorei ought, in my 

 opinion, to be considered as a distinct and interesting species." 



To this I may add that P. sujyerhus Heller, as re-described and 

 figured by Coutiere {t. c. p. 319, pi. xiii. figs. 34-37), grows to a 

 very much larger size than P. moorei ; and when specimens of 

 about the same size are compared, it seems to differ in having the 

 chelse smooth and beset with rather long hairs. P. niloticios 

 Roux, of which a specimen from the Blue Nile has recently been 

 presented to the Museum by Captain Stanley Flower, clearly 

 differs from P. moorei in many charactei^s. It is of much larger 

 size (the specimen before me is 41 mm. in total length) ; the 

 rostrum has a strongly convex upper edge with eleven teeth, of 

 which only one is on the carapace while the distal one is some 

 distance from the tip ; the lower edge of the rostrum bears two 

 teeth (Klunzinger and Heller agree in giving the number as 1-2, 

 so that Roux's figure, which shows five, is no doubt incorrect) ; 

 the merus of the second legs is three-fourths of the length of the 

 carpus, which is a very little longer than the chela ; the fingers 

 are about equal to the palm, and the whole limb is smoother than 

 in P. moorei. 



Occicrrence. — Off Niamkolo, 12.viii.04. " Dredged in about 

 12 fathoms, among shells." About sixteen females and one male. 



Kalambo, 4.xi.04. " Tow -netting, surface, 8.20 p.m." One 

 very j^oung specimen. 



Kirando, 1. xii. 04. " Taken in about 10 fathoms." One female. 



Mrumbi, 27.xii.04. " From about 30 fathoms." One male. 



Family Atyid^e. 

 Caridina nilotica, var. gracilipes (de Man). 



C. ivyckii, var. gracilipes de Man, in Weber's 'Zool. Ergeb. 

 Niederlandisch Ost-Indien,' ii. p. 393 (1891). 



All the prawns obtained by Dr. Cunnington from Lake JSTyasa 

 and the Victoria Nyanza belong to the genus Caridina, and to 

 that section of the genus including the forms to which the specific 

 names nilotica, longirostris, and loyckii, as well as a series of 

 varietal names, have been applied. It is not easy to determine 



