A REVIEW OF THE AMERICAN SPECIES OF TETRAODONTIDiE. 

 By DAVID »$. JOKDAIV aud CHARViKK L.. EDtVARDS. 



In the j)reseiit paper we have attempted to review the synonymy of 

 the American species of Puffers or Tetraodontidw, and to give analytical 

 keys by which the genera and species may be distinguished. The speci- 

 mens examined have been chiefly collected by Professors Jordan aud 

 Gilbert. These are in the museum of the Indiana University, while 

 duplicate series are in the U. S. National Museum. 



We accept the family of Tetraodontidw as including all the Plectog- 

 nathous fishes, in which the teeth in each jaw are coalesced into a bony 

 plate, which in each jaw is divided by a median suture. The American 

 species of this group, all referried by Dr. Giinther to the single genus 

 Tetrodon, fall into five grouj)s which are certainly natural and appar- 

 ently well defined, and which we regard as distinct genera. 



These may be defined as follows :* 



a. FroDtal bones articulated with the supraoccipital and the postfroutals confined to 

 the sides, the ethmoid little prominent to view above and short or nar- 

 row ; back not carinated ; snout heavy and broad; vertebra? in mod- 

 erate or small number (7 to8+i) to i;5)^ dorsal aud anal fins each with 6 

 to 15 rays ; skin smooth or more or less prickly, without scutes (Tetro- 

 dontince). 

 h. Frontal bones expanded sidewise and forming the lateral roofs of the orbits, the 

 postfroutals limited to the jjosterior portions. Marine species. 

 c. Nostril, on each side, with two distinct openings ; frontal region longi^r than 

 broad . 

 d. Dorsal and anal fins comparatively long, falcate, each of 12 to 15 rays; cau- 

 dal lunate; vertebrae about 20; nostrils sessile or nearly so, not form- 

 ing a distinct papilla; mucous tubes on upper part of head aud on 



sides of body very conspicuous Lagocephalus, 1. 



dd. Dorsal and anal fins comparatively short, rounded, each of 6 to 8 rays; 

 caudal usually rounded ; veHebrae about 8 -f- 10 ; nostrils at the summit 

 of a hollow, simple (or lobed) pax^illa; raucous tubes iucouspicuous. 



Sph^roides, 2. 

 ce. Nostril on each side, with a bifid tentacle, without distinct opening; frontal 

 region broader than long; fins and vertebrae as in S2)ha'roidcs. 



Tetkaudox, o. 



hi). Frontal bones narrowed and exchided from the orbit, the postfroutals being 



elongated and projected forwards and connected with the prefrontals; 



dorsal and anal fins short, rounded ; snout very obtuse ; vertebra? 8 + 11 ; 



nostrils (probably) as in Sj)liwroides. Fluviatile species. 



COLOMESUS, 4. 



*The osteological characters here given are mostly copied from Professor Gill's 

 "Synopsis of the Plectoguath Fishes" (Proc. U. S. Nat. Mus., 1884, 411), and were 

 by him derived chiefly from the plates in Hollard's "Etudes sur les Gymnodontes" 

 (Ann. des Sciences Naturelles, Paris, 1857, viii). 

 230 



