CHONDROPTERYGII. 647 



from the veins ' of the gills, which convey the blood that 

 has received the influence of respiration. They pass along 

 with the nerves to the electric organ, and enter with them, 

 then they ramify in every direction into innumerable small 

 branches upon the sides of the columns, sending in from the 

 circumference all around, upon each partition, small arteries, 

 which ramify and anastomose upon it, and passing also from 

 one partition to another, anastomose with the vessels of the 

 adjacent partitions. 



The veins of the electric organ pass out close to the nerves, 

 and run between the gills to the auricle of the heart. 



The nerves inserted into each electric organ arise by three 

 very large trunks from the lateral and posterior part of the 

 brain. The first of these in its passing outwards turns round 

 a cartilage of the cranium, and sends a few branches to the 

 first gill, and to the anterior part of the head, and then passes 

 into the organ towards its anterior extremity. The second 

 trunk enters the gills between the first and second openings, 

 and after furnishing it with small branches, passes into the 

 organ near its middle. The third trunk, after leaving the 

 skull, divides itself into two branches, which pass to the 

 electric organ through the gills, giving small branches to the 

 gill itself. These nerves having entered the organs, ramify 

 in every direction between the columns, and send in small 

 branches upon each partition where they are lost. 



The magnitude and the number of the nerves, bestowed on 

 these organs in proportion to their size, are very extraordi- 

 nary. Nerves are given to parts, either for sensation or 

 action. Now, if we except the more important senses of 

 seeing, hearing, smelling, and tasting, which do not belong 

 to the electric organs, there is no part, even of the most per- 



1 It may be proper to remind our readers that the veins of the gills, 

 like the pulmonary veins in terrestrial vertebrata, differ from all the other 

 veins in the body, by carrying pure arterial blood. 



