SEMEN. 



481 



tilia with scales. Lizards, snakes, and tor- 

 toises uniformly possess, like most birds, a 

 simple and straight body (Jig. 338.), which, 

 however, is occasionally rather pointed towards 

 the anterior part. This occurs, for instance, 

 in the snakes. The only difference consists 

 in the difference of breadth of body and 

 tail. In the snakes (Coluber), in which the 



Pig. 338. 



Fig. 339. 



Spermatozoa of Lacerta 

 agilis. 



Spermatozoon of Rana 

 temporaria. 



spermatozoa measure about -%"> the length 

 of the body amounts to only ^-3" ; in the 

 lizards (Lacerta), on the other hand, in which 

 the spermatozoa are smaller (-V // 3VO 

 about -vfe'". 



The differences of the form of the sperma- 

 tozoa are however much greater in the group of 

 the Batrachia, which likewise distinguish them- 

 selves in other respects by various deviating 

 circumstances. A staff-like body with a very 

 thin and proportionately short tail charac- 

 terise the spermatozoa of Rana and Bufo 

 (fig. 339.). The length of the spermatozoa 

 here amounts to about -^" ^o //r f which 

 the body occupies more than the anterior third. 

 Among the Salamanders the body is likewise 

 cylindrical, but much longer (/''), bent in 

 the shape of a sabre, and thickest at its pos- 

 terior end.* Towards the anterior part it 

 becomes gradually thinner, and (in Salamandra 

 at least) furnished at the point with a very 

 small globular knob. The tail is likewise of 

 a considerable length. In the anterior part, 

 which passes into the body, it possesses a 

 not inconsiderable thickness. Towards the 

 posterior part it becomes finer and thinner, 

 until at last it can only be traced with diffi- 

 culty. The end of the tail is, however, not 

 straight, nor curved like the anterior part, 

 but turned up in a remarkable manner, and 

 wound in very numerous narrow spirals 

 round the commencing part of the tail, and 

 even round the body. At least so we may ex- 

 plain the peculiar structure of the spermatozoa 

 of Salamandra, and in this we agree with 

 V. Siebold.f Others, especially French na- 

 turalists, as, for instance, Pouchet, merely 

 suppose the slender fibre, which is so twisted 

 round, to be the contour of a ridge-like 



* Vide copies in R. Wagner ; Fragment. Tab. II. 

 f Froriep's Neuen Notizen, vol. ii. S. 281. No. xl. 

 VOL. IV. 



formation, which is assumed to be seated on 

 the body lengthwise, and which is said to be 

 bent in a zig-zig manner to the right and 

 left. It is true that this fibre is frequently 

 only seen to rise on one side of the sperma- 

 tozoon, and in a shape which would encourage 

 the conjecture just now alluded to (jg.340.); 



Fig. 340. 



*4 



Part of Spermatozoon of Triton. 



a, body of the spermatozoon ; b, spiral windings of 

 the delicate tail. 



but in other cases the twistings are so distinct 

 that they are not to be denied. We are of 

 opinion that, whenever the tail has been lying 

 only on one side of the spermatozoon, a partial 

 twisting off has taken place. This notched 

 appearance may be attributed to the tail fibre 

 retaining its spiral twistings. It is, however, 

 remarkable that the tail never moves further 

 from the trunk of the body, constantly main- 

 taining only a certain distance from it. We do 

 not venture to decide the cause of this, yet we 

 cannot see in it a positive proof of the correct- 

 ness of Pouchefs view . 



The length of the spermatozoa is very con- 

 siderable. From the anterior point of the 

 body down to the region where the tail bends 

 itself, they measure in the Salamander -j*g-'", m 

 Triton even \'". The spermatozoa of the 

 Proteus seem to possess a still greater length, 

 according to an imperfect statement of 

 Valentin.* 



Fig. 341. 



Spermatozoa of Bombinator igneus. 



The spermatozoa in Bombinator igneus 

 (Jig. 341.) are of a structure quite similar to 

 those of the Salamander, only smaller. The 

 body of the former is staff-shaped, tolerably 

 long, and getting thinner towards both ends. 

 The point is again rather enlarged, and flat- 



* Repertorium fur Anat. &c. 1841, S. 356. 

 i i 



