326 



D. D. WHITNEY. 



FIG. i. Brachionus mulleri. A, normal spermatid showing the nucleus, chro- 

 matin, and the small tail; B, mature and normal spermatozoon showing the large 

 chromatin mass in the head and the long vibratile tail with the undulating mem- 

 brane. (Drawn by measurements from living and stained specimens with 1/12 

 oil immersion objective and a number 2 ocular.) 



