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PROCEEDINGS OP THE 



[July, 1857. 



first supra-orbital spine. External antennae with three peduncular 

 segments and a terminal filament, basal segment without the auri- 

 culiform appendage of Ranina. External maxillipeds of nearly 

 the same form as in Ranina, the third segment of nearly the 

 same breath as the second, and about equal to it in length, (M. 

 Edwards, by mistake, says that is longer,) and gives insertion 

 near its extremity to the fourth segment, which is folded in a 

 groove at the inner edge of the third segment. The sternal plate 

 resembles that of Ranina, is broad, widening anteriorly and 

 stretching out into two branches, which unite with the pterygosto- 

 mian regions of the carapax, separating completely the bases of 

 the external maxillipeds from those of the first pair of feet; 

 between the bases of the second pair of feet the sternal plate 

 becomes linear, as in Ranina, but it diners from that of Ranina, by 

 widening again between the bases of the third pair of feet, to 

 become again linear between those of the fourth, so that an, area 

 somewhat hexagonal is presented between the bases of the 

 second, third and fourth pairs of feet. In general structure, and in 

 the forms of the tarsi, the feet closely resemble those of Ranina, 

 and the fifth pair are inserted in that genus above the four prece- 

 ding pair, and a little in advance of those of the fourth pair. 

 Abdomen small, linear, when curved under the body, barely reach- 

 ing to the bases of the third pair of feet, cemposed in both sexes 

 of seven distinct segments, successively diminishing in dimen- 

 sions. 



RANILIA MURTCATA. 

 PL 13, Fig. 1 and 2, natural size. 

 Syn. Ranilia muricata. M. Edwards. Hist. Nat. des Crust., torn. ii. p. 196, 1837. 

 Ranilia muricata. L. R. Gibbes. Proc. Amer. Assoc., vol. iii. p. 187, 1850. 



Description. — Carapax posteriorly smooth, polished and punc- 

 tate, anteriorly marked with numerous dispersed piliferous 

 ridges, which are short and denticulate, with two to four obtuse 

 teeth, and pairs, as it were, oppressed, pointing forwards j the late- 

 ral edges of carapax terminating anteriorly in a prominent sharp 

 spine. Rostrum short. Eyts with straight terminal peduncle 

 folding downward and outwards in repose; supra-orbital ridge, 

 with three distant sharp spines, the outermost of these spines being 

 situated a little short of the outer angle of the orbit, and midway 

 between the first of these spine and the one forming anterior ter- 

 mination of lateral edge of carapax; between the spines are more 



