OCR Text |
Show 1906.] CRUSTACEA OF THE THIRD TANGANYIKA EXPEDITION. 191 unarmed part of upper edge much less than half its length, one or two sub-apical teeth, and occasionally an isolated tooth as above described. Carpus of first peraeopods not more than two and a third times as long as broad (in a series of specimens collected at Entebbe, by Mr. E. Degen, the carpus is only about twice as long as broad, sometimes a little less than twice). Carpus of second pair less than five times as long as broad. Dactylus of fourth pair a little more than one-fifth of propodus, with 8-11 spines; that of fifth pair more than one fourth of propodus, with 37-50 spines. Eggs "6 x *37 to *62 x *4 m m . Hilgendorf has recorded C. wyckii var. gracilipes from several localities in the Victoria Nyanza (Deutsch-Ost-Afrika, iv. (7) p. 36, 1898) and elsewhere in German East Africa. Prof. Bouvier, who does not quote Hilgendorf's work, records from Victoria Nyanza and from Doufile (Dufli) on the Upper Nile (about 3° 31' N . lab.) specimens which he regards as intermediate between the typical C. wyckii of de M a n and the South African var. paucipara Max Weber. The eggs in the specimens collected by Dr. Cunnington are rather smaller than those which Prof. Bouvier records from Lake Victoria, and much smaller than in the typical paucipara, while in other respects, such as the number of spines on the dactyli of the ambulatory legs, they show no approach to paucipara. Genus LIMNOCARIDINA. Limnocaridina Caiman, Proc. Zool. Soc. 1899, p. 704. To this genus, hitherto represented by only a single species discovered by Mr. Moore, I refer six of the new species found by Dr. Cunnington. As originally defined, the genus was distinguished chiefly by the great reduction of the branchial system, by the presence of a " hepatic " instead of an " antennal" spine on the carapace, and by the characters of the first and second maxilke and the first maxilliped. In all the species described below, the branchial formula agrees with that formerly given for L. tanganyikce, and there is no epipod on the first maxilliped. The structure of the maxillae is also essentially the same, though, in the second maxillae, the middle lobe is sometimes more expanded than it is in L. tanganyikce, but not overlapping the distal lobe. With regard to the spine on the carapace, however, the new species to be described below show that the difference between L. tanganyikce and the species of Caridina is one of position, not of homology. The spine, which in L. socius and L. spinipes is in the same position as the "antennal" spine of Caridina, is clearly homologous with that which, in L. latipes, L. similis, L. parvida, and L. retiarius, corresponds with what I formerly described as the " hepatic" spine of L. tanganyikce. In the following descriptions therefore I have abandoned the terms "antennal" and "hepatic," and speak simply of the " antero-lateral spine " of the carapace. In the original description of L. tanganyikce it is stated that the carpus of the first peraeopods |