i8 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I3I 



the ostracod limbs. Since we are here not particularly concerned with 

 the identification of the appendages, they have simply been numbered 

 on the drawings for purposes of comparison. 



/^' A 



4- 5 6 T 7 



Fig. 4. — Ostracoda. Larval stages of Cyprinotus hicongnicns Ramdohr (from 



Schreiber, 1922). 

 A, nauplius, with three pairs of appendages. B, second instar, with one pair 

 of added appendages {4) and caudal furca (/). C, fourth instar, with fifth ap- 

 pendages (5). D, fifth instar, with sixth appendages (6). E, sixth instar, with 

 seventh appendages (7). F, eighth instar, essentially adult structure. 



Inasmuch as in such forms as Limnocythere (fig. 5 A) the antennae 

 and the last three pairs of appendages have the form of segmented 

 legs, and in Cypris (B) the sixth and seventh appendages are typical 

 legs (E), it may be inferred that the primitive ostracod appendages 



