43 • 



immovable one. He is willing, however, to accept Gehiopsis 

 as a sub-genus for those species which are without the small 

 tooth on the antero-lateral margin of the cephalothorax (on a 

 level with the eyes and just over the second antennae). 

 This minute negative characteristic is shared, he says, by the 

 species 7iitidiu darivini, intermedia, and isodactyla, all of which 

 appear to have the fingers of about equal length. But if the 

 absence .of one spine justifies the sub-genus Gehiopsis for 

 these species, then the presence of three spines would seem 

 to demand another sub-genus for the Gebia spinifrons of 

 Haswell, in the description of which we find the " anterior 

 border, below the lateral frontal process, and behind the base 

 of the antennae, with three prominent acute spines." In 

 describing Gehiopsis inter media Dr. de Man speaks of " the 

 equally long fingers" of the chelipeds, but in the figures the 

 immoveable finger is much the shorter (J. Linn. Soc. London, 

 v. 22, p. 259, t. 16, f. 6, 7, 1888). Bell in his generic 

 definition of Gehia says, " the hand elongate, imperfectly 

 cheliform ; the moveable finger large, turning down to the 

 immoveable one, which is not half its length," and in his 

 description of " Gchia stellata " states that it has *' the 

 moveable finger long and slender, extending far beyond the 

 immoveable one," but immediately afterwards in his com- 

 parative description of " Gehia deltura " (which he regards 

 as doubtfully distinct from G. stellata) he declares that it 

 has " the fingers more nearly of equal length," and gives a 

 figure in which the right cheliped might fairly well pass for 

 perfectly cheliform. The Upogehia littoralis of Risso, which 

 when adult has the tooth on the antero-lateral margin and 

 the chelipeds imperfectly cheliform, is figured by Sars in the" 

 first postlarval form without the tooth and with the hands 

 forming " a perfectly normal chela, in that both the fingers 

 are of about the same length." The animal at this stage is, 

 however, only 5 mm. long. But already its mouth-organs 

 show a near approximation to those of the adult Lpogebia, at 

 least as seen in Upogehia capensis (Krauss). These also very 

 closely agree with the figures given in Savign)'^'s Crustacea 

 of Egypt, t. g, f. 3, for the species which Audouin doubtfully 

 identified with " Gehia stellata," but which H. Milue-Edwards 

 thought likely to require a new genus for its reception on the 

 ground that it differed from species of Gebia proper by having 

 the fingers of the chelipeds of equal length. As there is no 

 indication in the figure of an antero-lateral tooth, this species 

 will naturally fall to the Gehiopsis of Prof. Alphonse Milne- 

 Edwards, if that is upheld either as genus or sub-genus. But 

 there is no reason to expect that the mouth organs will help 

 to strengthen its dintinction from the parent genus. 



