566 ORDER PLECTOGNATHI. 



Diodon, L., (Vulg. Spiny globe-Jish.) 



Are thus named, because their jaws being undivided, 

 present but one piece above, and one below. Behind 

 the trenchant edge of each is a round part, furrowed 

 cross-wise, which forms a powerful instrument of 

 mastication. Their skin is armed on all sides with 

 thick pointed prickles, so that when they are inflated, 

 they resemble the fruit of a horse-chesnut ! . 



There is a considerable number of their species in 

 the seas of warm climates. 



Some have the prickles long, supported by two 

 lateral roots. 



The most common of this group, Diod. atinga, Bl. 

 125. and better, Seba. III. xxiii. 1, 2, attains to more 

 than a foot in diameter 2 . 



Others have short prickles on three divergent roots 3 . 



1 The jaws of this genus are not uncommon among petrifac- 

 tions. 



* Diod. histrix. Bl. 126, is the same species not inflated. I name 

 it to avoid all equivoque, Diodon punctatus. Add Diod. spinosissi- 

 mus, Cuv., Mem. Mus. iv. p. 134; Seb. III. xxiv. 10. Diod.lric- 

 dricus, Cuv., Mem. Mus. iv. p. 133; Seb. II. xxiii. 4. D. nicte- 

 mertis, Cuv., Loc. Cit. IV. vii. 5. D. novem-viaculatus, Id. ib. vi. 

 3. D. sex-fnaculatus, Id. ib. vii. 1. D. multimaculatus, Id. ib. 4. 



' Diod. tigrinus, Cuv., Mem. Mus. IV. vi. 1 ; or orbiculalus, Bl. 

 127 ; Seb. III. xxiii. 3. D. rivulatus, Cuv., ib. 2 ; or Maculato- 

 striatus, Mitchill, vi. 3 ; probably the Orbe, Lacep. I. xxiv. 3. D. 

 jaculifcrus, Cuv., loc. cit. vii. 3. D. antennatus, Id. ib. 2. 



