138 



THE GERM-CELLS 



G\' H 



K 



Fig. 67. — Spermatozoa of various animals. [A-I, L, from Ballowitz; J, K, from VON 

 Brunn.] 



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

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

 into two .parts (the posterior of these is perhaps a part of the nucleus). B. Insect {Calathus), 

 with barbed head and fin-membrane. C. Bird {PhyllopncHste). D. Bird (il//«f/V«/(7), showing 

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

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

 spermatozoon and ordinary form of Tadoriia. I. Ordinary form of the same stained, showing 

 apex nucleus, middle-piece and flagellum. J. " Vermiform spermatozoon " and. A', ordinary 

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

 greatly elongated middle-piece (w). and fiagellum (/). 



