238 MANUAL OF HISTOLOGY. 



oblong. In the last stage the granular body has become 

 changed into a long, thin, and homogeneous filament." 



" In what relation do, then, these different parts of the fully 

 formed spermatozoon stand to the parts of the developing ele- 

 ment that is, the spermatoblast? A comparison shows at 

 once that the head of the ripe spermatozoon is the changed 

 nucleus of the spermatoblast ; that the filament, or tail, is de- 

 rived from what has been mentioned above as the granular 

 body of the original cell. The middle piece of Schweigger- 

 Seidel is an outgrowth of the nucleus of the spermatoblast, 

 that is, of the head, the spermatozoon, and the clear tube of 

 the developing spermatozoon, described above as embracing 

 the hind part of the nucleus and separating the latter from 

 the granular body, is the sheath which, in some instances 

 (triton and salamander), is observable on the middle piece of 

 the fully formed spermatozoon." 



In short, the head of the spermatozoon is derived from the 

 nucleus, while the tail has its origin from the body of the sper- 

 matoblast. 



BIBLIOGRAPHY. 



^COOPER, A. Obs. on the Struct, and Dis. of the Testis. London, 1830. 

 WAGNER. Muller's Archiv. 1836. 



PANIZZA, B. Osservazioni anthropo-zoot. -fisiol. Pavia, 1836. 

 VALENTIN. Ueb. d. Verl. d. Blutgef. im Penis d. Menschen. Mailer's Arch. 1838. 

 ?KOBELT. Die mannl. u. weibl. Wollustorgane. Freiburg-, 1844. 

 KOLLIKER. Gewebelehre und Verhandl. d. Wiirzb. med.-phys. Ges. 1851. 

 ^KOHLRAUSCII. Zur Anat. u. Phys. d. Beckenorgane. Leipzig, 1854. 

 TAPPET. L'urethre de rhomme. 1854. 

 LEYDIG, F. Zur Anat. d. mannl. Geschlechtsorg. in Zeitschr. f. wiss. Zool. Vol. II. 



And Histologie. 1857. 



JARJAVAY. Rech. anat. sur I'urethre de rhomme. Paris, 1857. 

 MERKEL. Gottinger Nachrichten. No. 1. p. 7. 1863. And Arch. f. nrikr. Anat. 



Vol. I., p. 309. 1865. 

 r ST. GEORGE, v. LA VALETTE in Arch. f. mikr. Anat. Vol. I., p. 403. 1865. And 



Strieker's Manual. 



'PETTIGREW, in Proc. Roy. Soc. Vol. XV., p. 244. 1866. 

 * SCHWEIGGER-SEIDEL, in Virch. Arch. Vol. XXXV1L, p. 225. 1866. 

 BALBIANA. Journal de 1'anat. et de la phys., p. 218. 1868. 

 LETZERICH. in Virch. Arch. Vol. XLII., p. 570. 1868. - 



STIEDA. Ueber den Bau des Menschen-Hoden, Arch. f. mikros. Anat. Vol. XIV., 

 p. 17. 1877. 



