82 HISTOEY OF CRUSTACEA. Chap. VIII. 



portion of the embryo in the Biastylidse, as I have 

 recently observed, is curved upwards as in the Isopoda, 

 and the last pair of feet of the thorax is wanting. 



Equally scanty is our knowledge of the developmental 

 history of the Ostracoda. We know scarcely anything 

 except that their anterior limbs are developed before 

 the posterior one (Zenker). The development of Cyj)ris 

 has recently been observed by Claus : — " The youngest 

 stages are shell-bearing Nauplius-forms." 



applies to nearly all Crustacea. How well warranted are we therefore 

 in identifying the latter with the former. However, it is sufficient for 

 any one to glance at the larva of Palxmon (fig. 27) and the Cumaceau 

 (fig. 52) in order to be convinced of their extraordinary similarity ! 



