714 REPTILIA. 



(2019.) In the female Triton, as also in the Proteus and Siren, the 

 ovaria and oviducts offer precisely the same arrangement as that met 

 with in the Frog, already described *. 



(2020.) In the Ophidian, Chelonian, and Saurian orders, the testes 

 of the male sex are situated in the loins ; and in fact they occupy the 

 same position throughout the oviparous Vertebrata : they offer no pecu- 

 liarity of structure, only differing from those of the Prog in the in- 

 creased length of the now contorted seminal ca3ca of which they are 

 essentially composed. From each testis a long and flexuous vas deferens 

 conducts the semen into the cloaca. Here, however, in these more 

 elevated forms of the Eeptilia, we have another important addition to 

 the male sexual apparatus instruments being given to facilitate the 

 impregnation of the female during that union of the sexes which now 

 becomes essential to fecundity. The earliest appearance of the copula- 

 tory organ is seen in Serpents and in the Lizard tribes ; and in such 

 reptiles it will be observed that the penis is rather a provision for 

 securing the juxtaposition of the sexual apertures of the male and female 

 than an instrument of intromission. The two lateral halves of the penis 

 (or corpora cavernosa, as we shall have to call them hereafter, when they 

 become conjoined in the mesial line) are as yet quite separate, and placed 

 at each side of the cloaca! fissure, from which they protrude when in a 

 state of erection, so that there appear to be two distinct organs of 

 excitement, or, more properly speaking, of prehension ; for each division, 

 being of course imperforate, is covered with sharp spines, and is ob- 

 viously rather adapted to take take firm hold of the cloaca of the female 

 than to form a channel for the introduction of the seminal fluid. 



(2021.) In the Chelonian Reptiles the penis is much more perfectly 

 developed, and really constitutes a very efficient intromittent instrument. 

 The two corpora cavernosa, after commencing separately, approach each 

 other, and become united along the mesial line so as to form a single 

 organ of considerable size, terminated at its extremity by a glans- 

 like dilatation. There is, however, no corpus spongiosum, nor urethral 

 canal, properly so called : the latter is represented by a deep groove, 

 which runs along the upper surface of the penis from the cloaca to the 

 extremity of the organ ; and it is along this groove that the spermatic 

 fluid is conveyed during coitus. 



(2022.) On making a section of this strange apparatus, two canals 

 are discovered, running one on each side of the central furrow, along 

 the whole length of the organ as far as the glans, where they terminate 

 without at all communicating with the exterior ; but on tracing them 

 in the opposite direction, they are found to be derived from the perito- 

 neal cavity, into which they open by distinct orifices f. 



* Vide Rusconi, Observations anatomiques sur la Sirene, mise en parallele avec 

 le Prote"e et le Tetard do la Salamandre aquatique. Pavie, 1837. 

 t Cuvier, Anat. Comp. torn. v. p. 115. 



