28 



PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



Fig. 20.— Non-Striated Musculab Fibres, Isolated. (Klein.) 



The cross-markings indicate corrugations of the elastic sheath of the individual fibres. 



:• ■-, 



=m 





■;.;•■ 



¥ 





a 



■ 







; 



Fig. 21.— Various Kinds of Epithelial Cells. {Klein.) 



A, columnar cells of intestine ; B, polyhedral oells of the conjunctiva : C, ciliated conical cells of the> 

 trachea ; D, ciliated cell of frog's, mouth ; E, inverted conical cell of trachea ; F, squamous cell of 

 the cavity of the mouth, seen from its broad surface ; G, squamous cell, seen edgeways. 



Fig. 22.— Various Kinds of Spermatozoa. {Klein.) 



A, spermatozoon of guinea-pig not yet matured ; It, the same seen sideways, the head being flattened 

 from side to side j C, a spermatozoon of the horse ; D, a spermatozoon of the newt. 



