CRUSTACEA. 539 



40. Goniosoma natator (Herbst). 



A female was collcctod at Poivro Island, or lie des Roches, 13- 

 20 fms. (No. 183). 



Specimens arc in the British-Museum collection from the following 

 localities: — Port Natal; Indian Ocean [Gen. Hardvuicke) ; Penang 

 (Z>v. Cantor); Philippines ( Cuming) ; and Shanghai. 



47. Thalamita sima. M.-Edw. 



Several young specimens were collected at the Seychelles, 4-12 

 fms. (No. 11*4); a series of specimens of hoth sexes and varying 

 sizes at Poivre Island and He des Roches, 13-20 fms. (No. 1S3) ; 

 a young male at the Glorioso Islands, 7-10 fms. (No. 219); and a 

 female on the heach at Mozambique (No. 224). 



I have remarked upon the distribution of this common species on 

 p. 231. 



48. Thalamita quadrilobata. (Plate XLVIII. fig. P.) 



The carapace is markedly transverse, of the form usual in this 

 genus, depressed, with the lateral margins forming nearly a right 

 angle with the front ; the carapace marked with transverse lines, 

 one of which passes across it at its greatest width from the bases of 

 the fifth lateral marginal teeth, being interrupted only on the sides 

 of the gastric region by the shallow depression indicative of the 

 cervical suture. The frontal margin is divided into four squarely- 

 truncated lobes of nearly equal width ; the median lobes are more 

 prominent than the lateral, with their anterior margins very shallow, 

 concave, or excavate, and are separated by a narrow median in- 

 cision ; the lateral lobes have a straight margin. On the post- 

 frontal part of the carapace, on either side of the middle line, are 

 two slight prominences. The upper margin of the orbit has two 

 distinct fissures, the lower margin is also marked by a deep fissure ; 

 and the inner suborbital lobe is very prominent and squarely 

 truncated. There are five very strong, acute, subequal, lateral 

 marginal spines ; the postero-lateral margins are deeply concave ; 

 the posterior margin bounded by a raised line. The postabdomen of 

 the male is five-jointed; the third to fifth joints coalescent ; the 

 basal antennal joint is armed with three strong spines. The cheli- 

 pedes are massive and of equal size ; the merus or arm has its 

 posterior margin obtusely angulated, and its anterior margin armed 

 with three principal spines and one or two very small intervening 

 ones ; the wrist granulated externally, with two small spines on its 

 outer surface and a very strong spine on its inner margin ; the palm 

 granulated above and armed with five or six spines, externally 

 traversed by three granulated lines, of which the lowermost is pro- 

 longed along the outer margin of the immobile finger ; the fingers are 

 very distinctly denticulated, those of the right side having each a 

 larger subbasal tooth. The three following legs are slender ; the 



