THE SPERMATOZ01DS. 39 



OF THE SEMEN.* 



THE few additions which it is necessary to make to the chapter on the 

 subject of the semen, in the Physiology of Professor Miiller, may be 

 arranged under the following heads : 



1 . Varieties of form presented by the spermatozoids or spermatic fila- 

 ments. 



2. Their structure. 



3. Their motion. 



4. The influence of reagents upon them. 



5. Their modes of development. 



6. The question of their independent vitality. 



7. Their function. 



1. It would serve no good purpose to repeat here the description given 

 by Kolliker f and other recent observers J of the forms of the spermatic 

 filaments in the many species of invertebrate animals, in which they have 

 recently been examined. The general result at which Kolliker arrived, 

 with reference to the forms of the spermatic filaments was, that the 

 varieties of form, though manifold, are comprised within tolerably narrow 

 limits ; that the forms are almost always very similar in the same gemis, 

 and mostly so even in the same family and class; while in the same 

 species, never more than one form is met with. The apparent varieties of 

 form observed in certain instances in the same species of animals, are, 

 according to Kblliker's observations, only different stages in the develop- 

 ment of one form of spermatic filament. 



2. The notion that the spermatic filaments have an internal animal 

 organization, is now abandoned by the best inquirers on the subject. 

 Kolliker || declares that all the hair-shaped filaments, whether spiral or not, 

 are formed of a homogeneous substance. The same is the case, also, he 

 says, in by far the greater number of those that have a body distinct from 

 the filamentous part. With regard to the spermatozoid of the Bear, 

 Kolliker remarks that the circles imagined by Valentin H to be mouth, con- 

 voluted intestinal canal, and anus, may have been merely the appearances 



* Book vii. sect. ii. ch. iv. p. 1471, of Muller's Physiology. 



t Beitrage zur Kenntniss der Geschlechts-verhiiltnisse und der Samen-flussigkeit wirbel- 

 loser Thiere, Berlin, 1841. 



t Stein, Miiller's Archiv. 1842, p. 238. Von Siebold, Muller's Archiv. 1843, p. 21. 

 Rathke, Wiegmann's Archiv. 1842, i. p. 73. H. Meckel, Muller's Archiv. 1844, p. 473. 

 Will, Horse Tergestrinae and Wiegmann's Archiv. 1844, Bd. i. p. 337. Paasch, De Gasterop. 

 nonnull. hermaph. system, genitali et uropoetico. Diss. Berol. 1842. Miiller, Ueber den 

 Bau des Pentacorinus caput Medusae, Berlin, 1843, p. 177. 



Kolliker, Op. cit. || Op. cit. p. 64. 



t See Muller's Physiology, p. 1473. 



