B. III. j THE HISTOET OF ANIMALS. 47 



among these may be seen by dissection, and in another place 

 they will each be considered more particularly. 



4. All oviparous animals, whether bipeds or quadrupeds, 

 have their testicles placed in the loins below the diaphragm, 

 some of a white colour, others ochreous, but in all sur 

 rounded with small veins ; from each of these a passage is 

 produced, which afterwards become united in one, and, as 

 iu fish, open near the anus. This is the penis, which is in 

 conspicuous in small animals ; but in the larger, as the goose 

 and such like, it becomes more conspicuous immediately 

 after coition. 



5. And these passages, both in fish and other animals, 

 are joined to the loins below the stomach and between the 

 entrails and the great vein, from which passages proceed to 

 each of the kidneys ; and, as in fish, the semen may be seen 

 entering them at the period of coition, when these passages 

 become very conspicuous, but when this season is passed 

 the passages again become invisible. So also the testicles 

 of birds are either small or entirely invisible when not excited, 

 but when urged by desire they become very large ; this is so 

 remarkable in pigeons and partridges, that some persons 

 have supposed that they had no testicles during winter. 



6. In some of those animals in which the testicles are placed 

 forwards, they are internal and upon the abdomen, as in the 

 dolphin ; in others they are externally conspicuous upon the 

 extremity of the abdomen. These animals are similar in 

 other respects, but differ in this, for in some the testicles 

 are uncovered, and others that have external testes they are 

 placed in a scrotum. 



7. This is the nature of the testicles of all viviparous ani 

 mals with feet : from the aorta, passages like veins proceed 

 to the head of each testicle, and two others from the kidneys, 

 these last are full of blood, but those iVom the aorta con 

 tain no blood. From the head of each testicle to the tes 

 ticle itself, there proceeds a thicker and more muscular pas 

 sage, which is in each testicle reflected back to the head of 

 the testicle, and from this point they again unite upon the 

 penis towards the fore-part of it. 



8. And both these passages which are reflected back upon 

 themselves, and those which are seated upon the testicle*, 

 are covered with the same membrane as the testes them- 



