ICHTHYOLOGY. 23 



gives so forcible a shock as to throw down the 

 person who thus inadvertently annoys it. 



Q. What are the organs that produce this sur- 

 prising effect ? 



A. The electric organs of the Torpedo consti- 

 tute a pair of galvanic batteries, consisting of lit- 

 tle laminae or pellicles *, arranged in columns, and 

 separated by moisture. 



CHAPTER IV. 



Of Cartilaginous Fish (continued.) 



Q. WHAT are the principal genera of the Slen- 

 der snake-shaped kind Cartilaginous Fish ? 



A. There are but few genera of this kind of 

 Fish ; the Lamprey will serve as a specimen. 



Q. Are there not several species of this genus ? 



A. Yes ? there are eight species, having in com- 

 mon seven spiraculae, or breathing holes, on each 

 side the head ; no gill, a fistula, or spouthole, on 

 the top of the head, and no breast or belly fins. 

 The species are distinguished by peculiarities on 

 their back fins. 



* Lamina M pellicles are thin skins lying over one 

 another. 



