igio.] vS. Kemp: Notes on Decapoda. 179 



Gennadas bouvieri, Kemp. 



Gcnnadas bouvieri, Kemp, Pyoc. Zool. Soc, 1909, p. 726, pi. 

 Ixxiv, figs. I — 4; pi. Ixxv, figs. 6 and 7. 



St. 198.— North-east of Ceylon, 8=* 55' N., 81'' 17' 30" E., 764 

 fathoms. One female, about 25 mm. 



This specimen agrees closely with the description of the tj'pe. 

 The only important difference lies in the proportional length of 

 the joints of the third pair of peraeopods, where the merus is only 

 very slightly shorter than the carpus. Except for the fact that no 

 spermatophores are inserted, the thelycum is practically identical 

 with that figured in 1909 (pi. Ixxv, fig. 6). 



G. bouvieri was found by the 'Challenger' west of Manila and 

 north of New Guinea. 



Gcnnadas carinatus (vSmith). 

 (Plate xiv, figs. 4 — 9.) 



Benthesicynius? carinatus, Smith, Rep. U. S. Fish Conun. for 

 1882, 1884, P- 396, ph X, figs. 6 and 7. 



Gennadas carinatus, Alcock, Desc. Cat. Ind. Macrura. 1901, 

 p. 46. 



Gennadas carinatus?, McGilchrist, An)i. Mag. Nat. Hist., 

 March, 1905, p. 236. 



St, 128.— Oft" C. Comorin, 6° 58' N., 77° 26' 50" E., 902 

 fathoms. One male, 130 mm. 



St. 306. — Oft" Travancore, 9° 20' N., 75° 24' E., 930 fathoms. 

 One female, 148 mm. 



This large species is of great interest and, although the two 

 specimens in the Indian Museum have already been recorded by 

 Alcock and McGilchrist, a fresh description drawn up on the lines 

 of Bouvier's recent work may be found useful. 



I have followed Alcock in placing the species in the genus 

 Gennadas, though, in point of fact, it is almost exactly intermediate 

 in character between that genus and BoitJiesicvmus. In habit, 

 however, the two genera appear to be quite distinct, for Gennadas, 

 as far as at present known, is entirely pelagic, whereas Benthesi- 

 cynius lives on the bottom. Now in carinatus the joints of several 

 of the appendages are greatly flattened and expanded and closely 

 resemble those of the former genus, and this modification, which is 

 doubtless correlated with a free-swimming existence, has induced 

 me to retain the species in its present position. 



Alcock has, indeed, suggested that it might be best to regard 

 Gennadas as a subgenus of Benthesicy^nus, but from a practical 

 point of view this cannot be recommended. It must be remem- 

 bered that it is only in the present case that anj^ diificulty arises 

 in allocating the species to one or other genus. 



