072 the Torpedo of the Cape of Good H&pe. \ 5 



The columns of the electrical organs were larger, and less nu- 

 merous in proportion, than those described by Mr. Hunter, in 

 the torpedo cat'ght at La Rochelle. VVlien separate and unin- 

 fluenced by external j)ressure, they appear to be of the form of 

 cylinders, as is shown as nearly as possible by suspending them 

 by one of their extremities. The different forms which they 

 exhibit in a horizontal section of the whole organ, are produced 

 by their unequal attachmcut to one another by the intermediate 

 reticulai- substance. 



The electrical organs are so placed within the curvature of the 

 semilunar cartilages of the large lateral fins, as to be entirely 

 under the influence of the muscles, which are inserted into these 

 cartilages. So that in any lateral motions of these cartilages to- 

 wards the trunk, or in any increase of curvature of these carti- 

 lages, the electrical organs must be compressed. There appears 

 also to be a muscular structure, wliich connects the anterior 

 part of these cartilages to a process projecting from the anterior 

 part of the cranium, the action of which must tend to increase 

 this effect. 



The inferior and posterior terminations of the small lateral 

 fins are covered with lamiuse of osseous matter, which are en- 

 veloped in the epidermis. 



A much larger proportion of nerves is supplied to the electrical 

 than to any other organs. Tliis has appeared to others so im- 

 portant an ob.=?ervation, that it maybe repeated with propriety. 



The shocks received from the torpcdos which I examined, 

 were never sen: ihle above ths slioulder, and seldom above the 

 elbow-joint. The intensity of the shock bore no relation to the 

 size of the animal (sensation being the only measure of intensitv), 

 but an evident relation to the liveliness of the animal, and vice 

 versa. The shocks generally followed simple contact, or such 

 irritation as pressing, pricking or scueezing, sometimes imme- 

 diately, and sometimes not until after fretjuent repetition. Not 

 unfrcquently, however, animals apparently perfectly vivacious 

 suffered this irritation vvithout discharging any shock. There 

 appeared no regularitv of interval between tlie shocks. Some- 

 times they were so frequent as not to be counted ; at other time", 

 not more than one or two have l)een received from one animal ; 

 and, in a few instances, it has been impossible by any irritation 

 to ehcit shocks from some of them. When caught by the hand, 

 tliey sometimes writiied and twisted about, endcavoiuing to ex- 

 tricate themselves by muscular exertion, and did not, until the^' 

 iouud these means unavailing, discharge the shock. In manv 

 iu;tanccs, however, they had recourse to their electrical power 

 immediately. 



'i'hc elccLiical discharge was, in general, accompanied by an 



evident 



