178 



ly divided by constrictions into several portions. A single testicle 

 is most commonly found upon either side ; occasionally, however, we 

 meet with two and even several testes united one behind the other 

 merely by the seminal vessels, as is the case in the Salamanders, 

 where three to four such testes occur. The testes are invested ex- 

 ternally by a thick fibrous coat, and consist internally of long or 

 short and narrow cceca. The open extremities of these cceea pour 

 the seminal fluid into several ducts, which unite to form a straight 

 or contorted vas deferens, running down in front of the kidneys. 

 Both vasa deferentia open into the cloaca. Upon the testes, as also 

 upon the ovaria, there are appended occasionally in front, large 

 yellow-colored lobes of fat divided in a digitate form, e. g,, in the 

 Tailed Batrachia, while on the Anoura the adipose lobes are elon- 

 gated, undivided, and attached by mesentery to the internal side of the 

 sexual organs, or that turned toward the vertebral column. 



The Spermatozoa contained in the semen of the Reptilia exhibit 

 very numerous diversities. Those of the Squamigera, however, 

 present the greatest degree of uniformity. They have, in general, 

 in the common Snake for example, like those of Mammalia, an elon- 

 gated body pointed anteriorly, and a very fine filamentary tail. In the 

 Naked Amphibia greater varieties occur, while in the Frogs their 

 body is elongated and narrow, but not very long ; the spermatozoa 

 of the Tritons and Salamanders are slender and circularly contorted, 

 attain a very remarkable length, and exhibit very peculiar movements ; 

 other anomalous and singular forms occur, e. g., in Bombinator. 

 The spermatozoa are probably of largest size in the Proteus, thus ex- 

 hibiting an interesting analogy with the blood corpuscules. 



A proper external organ of copulation or sexual excitement, namely, 

 a Penis, is absent as a rule in all the Naked Amphibia, Batra- 

 chia as well as Ichthyodea. Still however in the Tritons, and in 

 some also, perhaps all the Ichthyodea, there is developed, at least 

 during the period of the coitus, an organ which may be viewed as 

 a rudiment of a penis. It consists of an acuminate papilla of con- 

 siderable size, situated within the cloaca, and continued poste- 

 riorly into two short thick crura, which form a groove with the 

 posterior wall of the cloaca, into which the semen is conveyed as it 

 issues from the adjacent mouths of the vasa deferentia. This pa- 

 pilla is imperforate, but, though very irritable, is incapable of erec- 

 tion. This structure resembles much the rudiment of the penis 

 that occurs in the male Ray-fish. Accessory glands occur in the 

 Ichthyodea and Tailed Batrachia. They consist of a very dense 



