209 



DIODON. 



This genus is found in all the tropical seas of the world ; its 

 body is covered with spines ; the fish can swell itself out as a 

 globe, and takes such an extraordinary appearance, that sailors 

 and travellers are very apt to collect it, as an object of 

 curiosity. There is no stronger proof of the semi-tropical nature 

 of all the Australian seas than the frequent occurrence of these 

 fishes in the most southern parts of this continent. Dr. Grunther 

 limits this genus of Linnaeus to the sorts who have "jaws without 

 a medium suture, body covered with dermal ossifications, each 

 with a pair of lateral roots, and with a stiff, moveable, and 

 erectile spine ; nasal tentacle simple, with a pair of lateral 

 openings." 



DIODOF SPIlSrOSISSIMTJS. 



Diodon Spinosissimus, Ouvier, Mem. Mus., vol. iv., p. 34. 



It is with great doubt I place under this name the present 

 fish, but having at my disposal no means of comparison, I 

 prefer not complicating still more the synonyma of a family 

 which requires already a special study, but I believe the 

 number of admitted species will, when this takes place, be 

 very much increased. General appearance of Diodon Histriac 

 of Bloch ; nasal tentacle formed of a short simple tube, with a 

 pair of lateral openings ; mouth small, its opening being less than 

 the diameter of the orbit ; spines very numerous, long, slender, 

 all of about equal length ; the root of each has three ridges ; the 

 tail has no spine, but there is one rather stronger than the others 

 on each side of the body at its base. Dorsal fin with twelve 

 rays ; caudal elongate, of eight rays ; anal of the size of the 

 dorsal, of twelve rays; pectorals of twenty-two. 



The body is, on its upper half, of a light green ; the lower one 

 is white ; on each side there are three faint black blotches of an 

 irregular form ; the spines and fins are of a light yellowish 

 green, those of the lower parts are white ; eye yellow ; no spots on 

 the fins. 



I have two specimens, both about three and a-half inches 

 long. 



