392 DR. W. M. TATTERSALL ON THE STOMATOPODA AND 



two joints are narrow, while in Pontonia they are broad. Ortmann makes 

 no mention of the form of the maxillipeds in his specimens. No one except 

 Nobili has recorded his species since. I have given reasons above for sup- 

 posing that Nobili's specimens were really referable to A. inermis, Miers. 

 The two characters of the rostrum and large chela I have already mentioned 

 provide the only points of difference between the two species. Are these 

 sufficient for specific differentiation ? An examination of Ortmann's type is 

 necessary to clear up this [joint. 



Distribution. New to the fauna of the Red Sea ; hitherto known from the 

 Indian Ocean. 



Genus Conchodytes, Peters, 1851. 



CONCHODYTES MELEAGRHSLE, Peters, 1851. 

 C. mehagrinee, Borradaile, 1917, p. 393. 



Locality. Uncertain. 40 specimens, 12-30 mm., labelled " Commensal 

 P.O. 13." 



Distribution. Previously recorded from the Red Sea by Nobili; Indo-Pacific 

 in Meleagrina and occasionally in Tridacna. 



Subfamily Pal ^emonin^e. 

 Genus Leander, Desmarest. 

 Leander tenuicornis, Say, 1818, p. 249. 



Leander natator, Nobili, 1906 a, p. 74. 

 Leander tenuicornis, Stebbing, 1914 a, p. 288. 



Locality. Station II , 1 ? , 37 mm. 



Remarks. My specimen agrees very closely with figure (i, pi. 128, of the 



9 

 'Challenger' Report except that the rostral formula is ^, two of the dorsal 



teeth being situated behind the orbit. The rostrum extends just beyond the 

 apex of the antenrial scale and is of the deep "latirostris " form. The con- 

 fusion which at present exists among the species of this family is well 

 exemplified in the species here in question. Stebbing (loc. cit.) has identified 

 the Leander natator of Milne-Ed wards and subsequent authors with the 

 earlier described Palwmon tenuicornis of Say. At the same time Stebbing 

 points out that this species agrees with Leander squilla in having the palp 

 of the mandible two-jointed. His description runs as follows: "the 

 mandibles have a very slender two-jointed palp, the second joint much the 

 longer." My specimen agrees exactly with this description. It should, 

 however, be pointed out that specimens in the British Museum labelled 

 Leander natator have, according to Caiman (Kemp, 1910, p. 130, footnote), 



