I02 



THE GERM-CELLS 



C 



H 



K 



Fig. 49. — Spermatozoa of various animals. [A~I, L, from Ballowitz ; y, A", from voN 



Brunn.] 



A. (At the left). Beetle (Cc//-m), partly macerated to show structure of fiagellum ; it con- 

 sists of a supporting fibre {s.f.) and a fin-like envelope (/.) ; tt. nucleus; a. a. apical body divided 

 into two pans (the posterior of these is perhaps a part of the nucleus). B. Insect (Calat/ius), 

 with barbed head and fin-membrane. C. Bird {PhyUopneuste). D. Bird {Muscicnpa), showing 

 spiral structure; nucleus divided into two parts («i, //-) ; no distinct middle-piece. E. Bulfinch; 

 spiral membrane of head. F. Gull (Lartis) with spiral middle-piece and apical knob. G. H. Giant 

 spermatozoon and ordinary form of Tiidonia. /. Ordinary form of the same stained, showing 

 apex, nucleus, middle-piece and flagellum. y. "Vermiform spermatozoon" and, K. ordinary 

 spermatozoon of the snail Paludina. L. Snake {Coluber), showing apical body {a), nucleus, 

 greatly elongated middle-piece (m), and flagellum ( f). 



