CLASS PISCES. 567 



Others, in fine, have slender prickles, like pins, or 

 hairs l . 



Tetraodon, L., 



Have the jaws divided in their middle by a suture, 

 so as to present the appearance of four teeth, two 

 above, two underneath. Their skin is furnished only 

 with small spines, not very prominent. Several species 

 are considered to be venomous. 



The most anciently known is that of the Nile. 



Tetraodon lineatus, L., Tet. physa, Geoff., Poiss. 

 d'Egypte, i. 1; Rondel. 419. (Fahaca of the Arabs, 

 Fiasco psaro of the Greeks, &c.) With back and 

 flanks striped longitudinally with brown and whitish. 

 The Nile throws out many of them on land during 

 the inundations, and they serve then as playthings for 

 the children. 



Some have the body compressed laterally, and the 

 back a little trenchant. These seem likely to be less 

 susceptible of inflation than the others : one of them 

 is electrical 2 . 



1 Diod. pilosus, Mitchill, fishes of New York, I. 471. 



2 The head and tail of the tetraodons are generally smooth, but 

 the rest of their body may be rendered more or less rough, by means 

 of the very small spines which issue from their skin. The various 

 combinations of the smooth and rough parts, and the configurations 

 which result from the more or less oblong forms of the head, have 

 allowed us to arrange them as follows : 



I. Species with short head, susceptible of inflation in a globular 

 form. 



1st. With the body rough throughout. 



[A. Without 



