CHAP, viii.] ORGANS OF RESPIRATION AND SECRETION. 245 



them all together, forming the spermatic cord before referred to. The 

 vas deferens is made of connective tissue enclosing a muscular coat, 

 the inside of which is mucous membrane, lined internally with 

 columnar but not ciliated epithelium. The two vasa deferentia 

 open into the urethra, as before described. 



22. The special secretion of the testis consists of certain sper- 

 matic filaments or SPERMATOZOA, which by their activity remind us of 

 detached cells of ciliated epithelium. They are not however the 

 equivalents of such cells, but of subdivisions of such cells. Each 

 spermatozoon consists of an oval flattened part called the "head" 

 or "body," and of a long and very slender filamentary "tail." 



Each spermatozoon is a peculiarly shaped cell of protoplasm, con- 

 taining a nucleus. The oval portion or head con- 

 sists of the nucleus enveloped in an extremely 

 delicate layer of protoplasm, which protoplasm 

 is continued on to form the filamentary tail. 



The spermatozoa are not the immediate product 

 of the testicular tubuli; these first produce ' sperm- 

 cells " or " spermospores," which constitute the 

 epithelium lining the tubuli. From these cells Fig , 117 _ 

 the spermatozoa appear to be formed by sub- ZOA OF THR CAT, 



,. . .^ . f* . J MAGNIFIED 320 DIA- 



division 01 the nucleus ot each spermospore ; the METERS, AND THEN 

 divisions of the nucleus forming the main part MM*J B 

 of the head of each spermatozoon, which is 

 completed from the non-nuclear substance of the dividing spermo- 

 spore. 



The vibratile, lashing action of the spermatozoon, only takes 

 place when it is fully developed. It will retain its power of move- 

 ment for some hours after its removal from the body if immersed in 

 a suitable fluid. By its lashings it effects a locomotive movement, 

 and it is thus admirably enabled to advance towards its proper 

 destination. Without the aid of these spermatic filaments no 

 reproduction of the cat species can take place. 



23. The FEMALE GENERATIVE ORGANS may, like those of the 

 male, be divided into (1) the external, and (2) the internal organs 

 the latter being the essential sexual parts. The functions of the 

 female organs are, however, more complex than those of the male. 

 The latter are destined to simply form and discharge their products, 

 but the female organs have not only to do this but also to receive 

 the male product and to protect and further that developmental 

 action which is initiated by the junction of that male product with 

 their own. The female organs consist, in the first place, of two 

 glandular structures, the ovaries, which secrete the female generative 

 product, the ova. Two tubes, one for each ovary, called the 

 Fallopian tubes, open into a median tubular structure, the uterus, 

 which is continued onwards to the exterior by the help of another 

 tube the vagina, immediately external to which is the uro- genital 

 chamber or vestibule, which is the most external portion of the 

 Avhole apparatus, and which opens on the surface of the body a 



