484 Mr. C. Spence Bate on the 



LV. — On the Willemoesia Group of Crustacea. 

 By C. Spence Bate, F.Bi.S. 



My paper on these Crustacea in the October number of 

 the '■ Annals ' was never intended to be exhaustive of the 

 subject ; but I certainly think that it was sufficiently clear to 

 have precluded questions and criticisms that without difficulty 

 might have been settled by one who has the advantage of 

 being in possession of specimens of the group. 



The Rev. A. M. Norman says ('Annals,' November, p. 382), 

 " I do not see my way at present to acquiescing in his conclu- 

 sions, and therefore venture to ask him to give us further in- 

 formation." 



His lirst question is, " Are his genera Pentachehs and 

 Willemoesia any thing more than the other sex of Poly- 

 chelesV 



Having just given a paper to prove that they are dis- 

 tinct and not one and the same species, I beg to repeat that 

 Pentachehs and Willemoesia are not the other sex of Poly- 

 cheles^ and to refer him to my paper for details. 



The next question is, " Has not my friend mistaken sexual 

 for generic characters'^ " to which I reply, most certainly not. 

 Then he asks, " Has he male and female of any Polycheles 

 or ?ix\j Pentachehs'^'''' in reply to which I wish to add the 

 following list : — 



Willemoesia hptodactyla, male and female. 

 Pentachehs Icevis . . female. 



Suhmi .... male. 



ohscurus . . . female. 



■ auriculatus . . female. 



gracilis . . . female. 



enthrix . . . female. 



Polycheles haccatus. . male and female. 



Helleri . . . male and female. 



crucifer . . . male. 



It will thus be seen that I have males and females of each 

 genus. 



I would, however, add that for some time I was hesitating 

 where several species of Pentachehs should be placed, as there 

 is a regular gradation from the imperfect to the perfect chelate 

 character of the fifth pereiopod ; but as I found Polycheles, 

 both male and female, with the simple non-chelate foot, at 

 present it appears to me that there is no arrangement so 

 constant as that which I propose. 



The next question the Rev. A. M. Norman asks is, " If so, 

 will he let us know how these sexes are distinguished ?" 



