MACRUROUS DECAPODA OF THE SUDANESE RED SEA. 873 



is about as long as the first joint of the carpus, and the fingers are about equal 

 in length to the palm. 



The third pair of legs (PI. 27. fig. 17) are slender, with the joints in the 

 following proportions, taking the finger as 1 : merus 2, carpus 1*5, pro- 

 podus 2"5, finger 1. 



The dactylus is simple, and there are spines on the inner distal margin of 

 the propodus. 



Among described species of the genus, A. crosslandi agrees with 

 A. dimorphus, A. minikoensis, A. haswelli, A. orientalis, and A. polymorplms, 

 to the exclusion of all the other species, by the combination of the two 

 characters, the absence of a supra-orbital spine on the carapace and the 

 simple character of the fingers of the last three pairs of legs. But the five 

 species mentioned all belong to ihe dimorphus group, and though there are no 

 male specimens of A. crosslandi available, the form of the first pair of legs of 

 the female point to its affinities with the nitescens group, in which its nearest 

 relative is A. naifaroeusis, Cout. It is, however, distinguished from the 

 latter species by the absence of a supra-orbital spine, and the great length 

 of the extra-corneal spine will serve to distinguish it from most of the 

 species of this group. 



Genus Synalpheus, Sp. Bate, 1888. 

 Neomeris group. 

 Synalpheus gravieri, Coutiere, 1905, p. 870, pi. 70. fig. 2. 



,S'. gravieri, De Man, 1911 b, p. 210. pi. 6. fig. 25. 



Locality. Station III., 2 $ , 10 and 12 mm. 



Remarks. The smaller of these specimens has only one spine and the 

 larger two spines, on the merus of the third pair of legs. Otherwise the 

 specimens are in close agreement with Coutiere's description. 



Distribution. The only previous record for the Red Sea is that of Coutiere 

 (1905) from Djibouti. Otherwise known from the Maldives (Coutiere, 1905), 

 Ceylon (Pearson, 1905 & 1911), Dutch East Indies (De Man, 1911), Chinese 

 and Japanese waters (Ortmann & Coutiere). 



Synalpheus streptodactylus, Coutiere, 1905, p. 870, pi. 70. fig. 1. 

 <S'. streptodactylus, De Man, 1911 b, p. 226, pi. 7. fig'. 29. 



Localities. Station IV., 1 (J,ll mm., 1 ? with eggs, 14 mm. 



Uncertain. 1^,10 mm., 1 ovig. ? , 14 mm., labelled Crust, fr. 44. 



Distribution. Not previously recorded from the Red Sea. Otherwise 

 known from the Maldives (Coutiere, 1905), Ceylon (Pearson, 1911), Dutch 

 East Indies (De Man, 1910), Atjeh and Ternate (De Man). 



