SEMEN. 



479 



the developement of the spermatozoa of this 

 bird.* The vesicles of developement, in this 

 instance, have a size of *&/" T$T/"' The y 

 are as clear as glass when in a fresh state, 

 and the spermatozoon in the interior can very 

 readily be observed. At the commencement 

 they are globular. Subsequently the shape 

 becomes more irregular ; sometimes it assumes 

 that of a pear, until finally the enclosure 

 bursts (which generally takes place at the 

 sharp extremity), when the spermatozoon 

 makes its exit with the tail end first (fig. 330.). 



Fig. 330. 



Spermatozoa of the Cock partly enclosed by the Cell 

 of Developement. 



For some time afterwards, the remainder 

 of the vesicle of developement may be seen 

 adhering to the separate spermatozoa. 



All the cells of developement, however, 

 are not free. We often find large cystiform 

 globules, enclosing a number of three, four, 

 eight, twelve, or sixteen cells of developement, 

 much more frequently than among the mam' 

 nialia; these generally have a diameter of 

 T&O"' im'" /" But the persistency of 

 these mother cells does not hinder the de- 

 velopement of the spermatozoa in any way. 

 The enclosed cells of developement are 

 equally as capable of producing these forma- 

 tions as the free ones, as one may readily 

 convince oneself by observation through the 

 microscope (Jig. 331.). On the destruction 



Fig. 331. 



A Mother Cell from the Cock, with three Spermatozoa 

 still enclosed in their Cells of Developement. 



of the membrane of the cells of develope- 

 ment, the spermatozoa get into the in- 

 terior of the cysts (fig. 332.), where they 

 lie together often in a great number, but never 



* Lehrbuch der Physiol. 3d edit. 18. S. 27. 



in regular fascicular groups. Finally, this 

 cyst also gets dissolved, without, however, 



Fig. 332. 



A Mother Cell from the Cock, with Spermatozoa free 

 in its interior. 



having changed its shape in any remarkable 

 way previously. The spermatozoa common 

 to each cyst, however, remain together for a 

 time, being connected by means of the tough 

 albuminous contents of the mother cell. 

 Thus, at least, we feel inclined to explain 

 the occurrence of irregular groups of sperma- 

 tozoa, which, kept together by one common 

 cement, not unfrequently occur in the semen 

 of the cock. 



According to our observation, the develope- 

 ment of the spermatozoa of the woodpecker 

 and of the pigeon takes place in precisely the 

 same manner; and this may be said likewise 

 of singing birds.* The cells of developement 

 of the latter are however still more rarely to 

 be met with free, and are perhaps always en- 

 closed by mother cells. The number of the 

 enclosed cells is generally very considerable 

 (/g.333.). 



Fig. 333. 



Cyst of the House Sparrow, with enclosed Cells of 

 of Developement. 



The formation of the spermatozoa in the 

 interior of the individual vesicles of develope- 

 ment is likewise very difficult to be traced, 

 principally because the contents of the latter 

 coagulate very readily, thus covering the 

 spermatozoa, and rendering them indistinct. 

 We have, however, succeeded several times 

 in observing the spermatozoa in the house 

 sparrow in the interior of their cells of form- 

 ation (fig. 334.). It certainly requires some 

 practice to discover the windings of the body 

 between the granules of the contents, the 



* Vide R. Wagner's figures in Miiller's Ar- 

 chiv. 1836, S. 225., in Fragm. zur Physiol. der 

 Zeugung ; in Lehrbuch der Physiolog. 17. S. 25. ; 

 as also in the Icon. Phys. tab. I. fig. 5. (copied in 

 the article, ENTOZOA, Vol. II. p. 112.), which 

 however, in consequence of our recent researches, 

 require some correction. 



