312 



D. D. WHITNEY. 



'3.ASPLANCHNA 

 AMPHORA 



4;POLYARTHRA 

 PLATYPTERA 



5.HYDAT1NA 

 SENTA 



6.DIGLENA 



CATELLINA 



7.EUCHLANIS 

 DILATATA 



S.METOPIDIA 



LEPADELLA 



9.BRACHIONUS 

 URCEOLARIS 



IO.BRACHIONUS 

 BAKERI 



FIGS. 3-10. Dimorphic spermatozoa of eight species of rotifers showing the 

 larger, motile, and functional spermatozoa and the smaller, immotile, and rudi- 

 mentary spermatozoa. In all of these species the drawings were made of sperm- 

 atozoa that were taken from mature free-swimming males except in Fig. 4 which 

 were made of spermatozoa of unhatched immature males. All were drawn to 

 same scale as Figs. 1-2. 



