VOL. LXV.] PHILOSOPHICAL TRANSACTIONS. 67 1 



bestowed on any other part for the purposes of sensation and action ; but it ap- 

 pears to me, that the organ of the torpedo is supplied with much the largest 

 proportion. If all the nerves which go to it were united together, they would 

 make a vastly greater chord, than all those which go to the organ of this eel. 

 Perhaps when experiments have been made on this fish, equally accurate with 

 those made on the torpedo, the reason for this difference may be assigned. 



Blood Vessels. — How far this organ is vascular, I cannot positively determine ; 

 but from the quantities of small arteries going to it, I am inclined to believe, 

 that it is not deficient in vessels. The arteries arise from the large artery which 

 passes down the spine ; they go off" in small branches like the intercostals in the 

 human subject, pass round the air bladder, and get upon the partition together 

 with the nerves, and distribute their branches in the same manner. The veins 

 take the same course backwards, and enter the large vein which runs parallel 

 with the artery. 



PI. 14, fig. I, Shows the whole animal of •§■ the full size. It lies on one side ; which posture 

 exposes the whole of the under fin. The head is twisted, to show its upper part, on which 

 are seen the eyes, &c. 



Fig. 2, Shows the animal lying in the same position, but the head is twisted in the contrary 

 direction, so as to expose its vmder surface. Between the two fins, and before the beginning of the 

 under fin, is the cavity of the belly of the fish ; at the anterior part of which cavity is the anus. 



Fig. 3, Exhibits the whole of the two organs on each side, the skin being removed as far as 

 these organs extend, a The lower surface of the head of the animal ; b, the cavity of the belly , 

 c, the anus; D, the fin; e, the back of tlie fish where the skin has not been removed; rv, 

 the fin which runs along the lower edge of the fish; ecG, the skin turned back; hhii, the 

 lateral muscles of the above fin removed and carried back with the skin, to expose the small organ. 

 1. Part of the muscle left in its place, kkk, the large organ j lll, the small organ ; mm mm, 

 the substance which divides the large organ from the small ; n, at this place the above substance is 

 removed. 



Fig. 4, Is a section of the whole thickness of the fish near the upper part. The skin is removed 

 as far back as the posterior edge of the organ, and the other parts immediately belonging to it, such 

 as the medulla spinalis. There are several pieces or sections taken out of the organ, which expose 

 every thing that has any relation to it. At the upper and lower ends of the figure, ff, the organ 

 is entire, the skin only being removed, a a. The body of the animal near the back, covered by the 

 skin; BB, the belly-fin, covered also by the skin; c, part of the skin removed from the organ, 

 and tiuned back ; dd, the muscles which move the fin laterally, and which immediately cover the 

 small organ ; k, the middle muscles of the fin, which lay immediately between die two small organs ; 

 TF, "the outer surface of the large organ, as it appears when the skin is removed ; g, the small 

 organ, as it appears when the lateral muscles are removed ; 11 11, tlie cut ends of the muscles of the 

 back, which have been removed to expose the deeper seated parts; 11, the cut ends of the large 

 organ, part of which has also been removed, to expose the deeper seated parts ; k, the cut end of 

 the small organ ; l, a part of the large organ, the rest having been removed ; M, the cut end of the 

 above section ; n , a section of tlie small organ ; 00, the middle partition which divides the two large 

 organs ; p, a fatty membrane, which divides the large organ from the small ; <j, the air bladder ; r, 

 the nerves going to the organ ; s, the medulla spinalis ; t, the singular nerve. 



Fig. 5, is a transverse section of the fish, exposing at one view, all tlie parts of which it is com- 

 posed ; A, the external surface of the side of tlie fish ; a, the under fin ; cccc, the cut ends of tha 



