MACEUEOUS DECAPODA OF THE SUDANESE EED SEA. 371 



nature of the material at my disposal this can be no more than a mere 

 suggestion. The specimens are too few and too fragmentary for a definite 

 statement, but perhaps Mr. Kemp himself at some future time may be able 

 to clear the matter up by personal observation on living material. 



Distribution. Djibouti and Minikoi (Coutiere) and Funafuti (Borradaile). 

 Also recorded from an unnamed locality in the Red Sea by Nobili. 



Athanas dimoephus, Ortmann, 1894, p. 12, Taf . I. fig. 1. 



(PI. 28. figs. 23-24.) 



Locality. Station I. B, 1 $ , 15 mm., and 1 9 , 14 mm. 



Remarks. The female has lost both legs of the first pair so that it is not pos- 

 sible to be quite sure of its identity. It agrees, however, very closely with the 

 male caught with it, and I have no doubt belongs to the same species. This 

 male specimen I identify with Athanas dimorphus, Ortmann, in spite of some 

 differences, mainly in the form of the first pair of legs. These appendages 

 are both fortunately present in the specimen. They are not equal in size, 

 the right being slightly the larger of the two, and the degree of difference 

 between the right and left being of much the same extent as exists in 

 A. djiboutensis. The movable finger of the right leg bears a prominent 

 tubercle on its inner margin near the base, while the fixed finger has a larger 

 and broader tubercle on its inside margin (PL 28. fig. 23). The condition 

 of the right chela in this specimen is, in fact, very much as I have noted in 

 J., djiboutensis. The smaller left chela is shown in PI. 28. fig. 24. The 

 fixed finger here bears a smaller and more obscure tubercle in the same 

 position as the prominent one on the right chela. This male specimen there- 

 fore corresponds to Kemp's male form III., and as such is evidence that 

 A. dimorphus likewise has truly dimorphic forms of the fully-grown male, 

 corresponding with what I have described in A. djiboutensis above. It is 

 somewhat extraordinary that Coutiere, who has apparently seen numerous 

 specimens of this species from various localities in the lied Sea, did not come 

 across this second form of the male, for I can find no reference to the 

 tubercles on the inner margin of the chela in any of his descriptions. 



Distribution. Red Sea at Suez, Perim, and Djibouti (Coutiere). Dar-es- 

 Salaam, E. Africa (Ortmann). 



There are two further specimens of Athanas in the collection which may 

 be provisionally referred to this species with considerable doubt. Both are 

 females, taken on the Suez Mud Flats, and neither of them possesses any of 

 the walking-legs. They differ from A. dimorphus in the form of the extra- 

 and inf ra-corneal spines of the carapace. 



The extra-corneal spine is shorter than the infra-corneal spines and does 

 not reach more than half-way across the corneal face of the eye. Both spines 

 are moreover broader and less acute than the same spines in A. dimoiyhus. 



