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Show 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 m e to be the most nearly allied to P. moorei as you suggest. Like Coutiere (Ann. Sci. Nat. 8 m e ser. xii. p. 324), I think that P. superbus Heller and P. trompi de Man, especially the former, are the most closely allied species. P. scabricidus Heller and P. alcocki Nobili 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 fingers, &c. P. scabricidus differs in the carapace, which is scabrous, in the rostral teeth, of which six are set on the carapace, 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. superbus 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 chelae smooth and beset with rather long hairs. P. niloticus 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 characters. It is of much larger size (the specimen before m e is 41 m m . 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. Occurrence.-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 young 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. Niederlanclisch Ost-Indien,' ii. p. 393 (1891). All the prawns obtained by Dr. Cunnington from Lake Nyasa 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 ivyckii, as well as a series of varietal names, have been applied. It is not easy to determine |