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Show 1906.] CRUSTACEA OF THE THIRD TANGANYIKA EXPEDITION. 195 Kituta Bay, 27.viii.04. " Tow-netting, surface, 8.30 p.m." Two specimens. Mbete, l.x.04. "Taken shore-wading." One female. Kasawa, 7.X.04. "Tow-netting, 8.30 p.m." Many specimens. Kalambo, 4.xi.04. " Tow-netting, 8.20 p.m." Three specimens. Kazagga, 7.iii.05. " Taken close to shore." One specimen. LIMNOCARIDINA SIMILIS, sp. n. (Plate XII. figs. 15-22.) Description.-Body slender; sixth somite of abdomen shorter than the carapace, its length about two and a half times its depth. Rostrum (Plate XII. fig. 15) a little longer than antennular peduncle, equal to or shorter than carapace, slightly arched at base, then horizontal, teeth -~£p-, unarmed above for half its length. Antero-lateral spine of carapace set well back from front edge. Antennular peduncle reaching to external tooth of antennal scale. Distal edge of scale (Plate XII. fig. 16) projecting well beyond external tooth. Third maxilliped not reaching to end of second segment of antennular peduncle, terminal segment little shorter than preceding. First peraeopods (Plate XII. fig. 17) short and stout, reaching to about the first third of first segment of antennular peduncle, breadth of carpus about three-fifths of its length, chela more than one and a half times as long as the carpus, twice as long as broad, fingers equal to the palmar portion. Second peraeopods (Plate XII. fig. 18) reaching a little beyond first pair, breadth of carpus about one-third of its length ; chela little longer than carpus, three times as long as broad, palmar portion two-thirds of length of fingers. Third peraeopods extending beyond and fifth pair falling considerably short of tip of third maxillipeds; dactylus of last three pairs more than one-third of propodus, that of third and fourth (Plate XII. fig. 19) with 14-15, that of the fifth (Plate XII. fig. 20) with 21 spines. Telson (Plate XII. fig. 22) four-fifths of length of sixth abdominal somite. Outer plate of uropods longer than inner. Total length, $ , 16*5 m m . Eggs '28 x *18 m m. Remarks.-This species is closely allied to L. tanganyikce, but is distinguished by the much shorter rostrum. One very remarkable feature is the strongly marked difference between the sexes in the armature of the third and fourth peraeopods. In the male (Plate XII. fig. 21) the marginal spines on these segments greatly exceed in size those of the female. A similar difference. though less strongly marked, is found in the species described below as L. socius, but in the other species of the genus I have not been able to perceive any difference between the sexes in this respect. Occurrence.-Kalambo, 4.xi.04. "Tow-netting, 8.20 p.m " One specimen. Rusisi ftiver, close to Tanganyika, 7.iii.05. Many specimens, mostly females. PROC. ZOOL. Soc-1906, VOL. I. No. XIV. 14 |