GLOBE-FISHES. 



689 



atilis from brackish water and rivers of the East Indies. The 

 species figured is one of the smallest, about six inches long, 

 and common in the Indo-Pacific. 



DiODON. — Jaws without mesial suture, so that there is only 

 one undivided dental plate above and one below. 



In these fishes, as well as in some closely allied genera, the 

 dermal spines are much more developed than in the Tetro- 

 donts ; in some the spines are erectile, as in Diodon, Aiopo- 

 mydertis, Trichodiodon, and Trichocydus ; in others they are 

 stiff and immovable, as in Chilomycterus and Dicotylichthys. 

 Seventeen species are known, of which Diodon hysirix is the 

 most common as it is the largest, growing to a length of two 

 feet. It is spread over the Tropical Atlantic as well as Indo- 



Fig. 313. — Diodon maculatns. 



Pacific, as is also a smaller, but almost equally common 

 species, Diodon maculatus. 



Fig. 314. — Diodon maculatus, inflated. 



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