REMARKS ON THE SEXES OF SPH^ROMIDS 



WITH A DESCRIPTION OF A NEW 



SPECIES OF DYNAMENE. 



BY SAMUEL J. HOLMES. 



Plate XXXIV. 



The genera of the family Sphseromidse are in a state 

 of annoying confusion. Differences of age and sex have 

 led, in some cases, to the establishment of more than one 

 genus for members of the same species. In cases where a 

 marked sexual dimorphism is supposed to exist, little has 

 been accomplished towards connecting the forms with their 

 proper mates. And aside from this there is more than the 

 usual amount of difference of opinion regarding the validity 

 and the limits of the genera into which this family has been 

 divided. 



M. Hesse ^ who has devoted a memoir to the sexual rela- 

 tions of the Sphasromidas came to the conclusion that he 

 had made a discovery which would greatly simplify mat- 

 ters; Sphceroma he believes to be only the female form of 

 Cymodoce, and Dynaniene the female of Ncesa. The evi- 

 dence upon which Hesse bases both his conclusions is, how- 

 ever, all indirect. Regarding the first conclusion he makes 

 the interesting observation that " depuis que notre attention 

 s'est fixee sur ses Crustaces, c'est-a-dire depuis plus de 

 vingt ans, nous n^ divons jamais vu un seul Cymodoceen adulte 

 qui eut des oeufs, tandis que nous avons toujours trouve 

 des Spheroniiens adulies qui en avazent, et nous avons 

 meme pu suivre leur eclosion et elever les jeunes." But 

 he adds: " Malheureusement nous n'avons pas pu mener 



1 Ann. Sci. Nat. ser. 5, t. 17, 1872. 



[ 295 ] October 4, 1904. 



