1 Review of American Diodontidm, 297 



XVI. — A Review of the Genera and Species of Diodontidm 



found in American seas. 



BY CAKL 11. KIGENMANK" 

 Read December 21, 1885." 



At the suggestion of Dr. David 8. Jordan, T have made a study 

 of the American Diodontidm, with a view to ascertain the num- 

 ber of valid species and their correct nomenclature. I give in 

 this paper the synonymy of the species recognized, with keys for 

 their identification. The specimens studied belong to the Mu- 

 seum of the Indiana University, at Bloomington, Ind. Some 

 important questions in regard to the species cannot be settled 

 without a greater amount of material than has been at my dis- 

 posal ; but it is believed that the conclusions here reached rep- 

 resent some advances in our knowledge. I am indebted to Miss 

 Rosa Smith for the description of two specimens from La Paz, 

 at San Diego. 



The American genera are two, which may be defined as fol- 

 lows : 



a. Body moderately inflatable ; head broad : nasal tentacle in front of eye, 

 with two lateral openings ; jaws without median sutures ; vertical 

 fins rounded ; pectorals short, broad. 

 b. Spines slender, mostly two-rooted, erectile ; in the three-rooted spines, 

 the anterior root is formed by a prolongation of the anterior ridge 

 of the spine. 



DlODOtf, 1. 

 66. Spines robust, all three-rooted, fixed ; the anterior root similar to 

 the lateral roots. 



Chilomycterus, 2. 



