AND THEIR FUNCTIONS. 167 



Evidently, therefore, the organs serving to secrete the 

 semen were, according to him, the seminal ducts, and the 

 testes were adjuncts sufficiently important, in some cases, to 

 ensure their efficiency. In some cases, the ducts could act 

 without the aid of the testes, for, in many passages, he 

 makes it clear that there were no organs to which he could 

 give the name testes in some animals, viz., in snakes, fishes, 

 and all animals with gills.* He was probably deceived 

 mainly by the usually elongated and duct-like form of the 

 testes in these animals. Cartilaginous fishes usually have 

 testes of a compact form, but it is not clear whether he in 

 tended to include these fishes within the meaning of the 

 passages above cited. Probably he did not, for he often 

 describes the cartilaginous fishes as if they were a separate 

 and distinct group. 



In a long series of passages in H. A. iii. c. 1, ss. 7-9, 

 Aristotle gives a remarkable description of the anatomy of 

 the testes of what are now called mammals, and exemplifies 

 his meaning by reference to a drawing, which has been lost. 

 This description was evidently based on one or more dis 

 sections. Notwithstanding many difficulties in the Greek 

 text, it is evident that he had some knowledge of the 

 spermatic arteries, the epididymis, the vas deferens and its 

 communication with the urethra, and the tunica vaginalis, 

 part of which envelops the epididymis. He states that the 

 testes are not of flesh, but are nearly of the nature of flesh.! 

 The second part of this statement is incorrect ; each testis 

 is composed chiefly of a very large number of seminiferous 

 tubules, enclosed within a strong, white, fibrous envelope. 



Among the numerous statements he makes about the 

 male organs of particular kinds of animals are some of 

 special interest. He says that the testes of the elephant 

 are near the kidneys,! and that the testes of some animals, 

 e.g., the lizard, tortoise, crocodile, and hedgehog, are in the 

 region of the kidneys, but some have them near the 

 abdominal wall, like the dolphin and elephant. 



The first statement, relating to the elephant, is quite 

 correct, for, according to Dr. M. Watson, the testes, which 

 are nearly globular, lie below the posterior ends of the 

 kidneys. |j The testes of the dolphin are abdominal, and lie 



* H. A. ii. c. 9, ss. 1 and 2, ii. c. 12, s. 10, iii. c. 1,8.1; P. A. iv. 

 c. 13, 697a; G. A. i. c. 3, 7166. 



| H. A. i. c. 10, s. 4. I Ibid. ii. c. 3, s. 4. Ibid. iii. c. 1, s. 2. 

 || Journ. Anat. and Physiol. vol. vii. 1873, p. 65. 



