ANCEUS. 



177 



ovi-pouch : the young of one animal appearing to be 

 all males, those of another being all females, so that 

 the variation may have been the result of an older or 

 younger stage of development. 



But, however great the similarity may be between the 

 two sexes at the time of their first leaving the ovi-pouch 

 of the parent, they very soon exhibit a distinguishable 

 variation, as seen in the woodcut on the preceding page, 

 in which fig. 1 (of which IA is an enlarged figure, seen 

 laterally) represents the male larva. That of the female 

 (figs. 2 and A, seen laterally) has the three posterior 

 segments of the pereion losing their crustaceous and seg- 

 mental character, and putting on that of a membranous 

 condition, and becoming fused together into one long 

 segment. 



That of the male, as shown in fig. 1, of which IA 

 is an enlarged representation (seen laterally), has the 

 segments well defined and crustaceous, but the central, 

 that is the third (though homologically the fifth), seg- 

 ment of the pereion, considerably increased in length, 

 with the coxae partially fused with the segment. Viewed 

 laterally, this segment is dorsally elevated above those 



DEVELOPMENT OF ANCEUS. 



Fig. A. Young of Anceus Edwardii (p. 201). Fig. B. Eggs, Fig. c. Young 

 of Anceus Maxillaris (pp. 176 and 192). 



VOL. II. 



N 



