138 



THE GERM-CELLS 



n U 



C 



// 



K 



Fig. 67. — Spermatozoa of various, animals. [./-/, Z., from Rallowitz; J, K, from von 

 Brunn.] 



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

 sists of a supporting fibre {s./.) 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). /A Insect {Calathus), 

 with barbed head and fin-membrane. C. Bird (Phyllopucnste). D. Bird { Muscicapa), -.how'mg 

 spiral structure; nucleus divided into two parts («i. «-) ; 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 Tadorna. /. Ordinary form of the same stained, showing 

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

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

 greatly elongated middle-piece {in), and flagellum f /). 



