188G.J PROCEEDINGS OP UNITED STATES NATIONAL MUSEUM. 23l 



aa. Frontal bones separated from tbe supraoccipital by the intervention of the post- 

 frontals, which are connected together and laterally expanded but 

 short, the ethmoid prominent above, enlarged and narrowed forwards; 

 nostrils obsolete, imperforate; head compressed, the snout slender and 

 produced ; back compressed to a sharp edge or keel ; dorsal and anal 

 fins short and rounded (rays 5 to 8); vertebra} 8 + 9 ; skin smooth or 

 prickly, without scutes {Cauihigastcrince) Cantuigaster, 5. 



I.— LAGOCEPHALUS. 



Tetkaodon species, Linnieus and of early authors (not type, as later restricted). 

 Lagockpiialus Swaiuson, Nat. Hist, and Class'n Fishes, ii, 194, 328, 1839 (s/e?/a/«s ; 



peinianti ^: Jagoceplialus L.). 

 PHYSOGASTERMiiller, Abhandl. Akad.Wiss., Berlin, 1839 (1841), 252 (Z« nans; ohlongus); 



(name preoccupied). 

 Gasxrophysus Mliller, Wiegmann's Archiv. ix, 330, 1843 (^/Mwaris). 

 Les Promecoceph<ales (Promecocephalus) Bibron, MSS., R6vue deZoologie, 1855, 279 



(aryndatus ; lunaris ; spacUceus; Imvigatiis ; lagoce2>halus{"Bloch,Tiec'L."y, htermls). 

 Gastrophysus Bleeker, Nat- Tydskr. Ned. lud., «&c., about 1855. 

 Tetrodon Gill, Cat. Fish. East. Coast N. Am., 1873, 15 {Iwvigatus, &c.). 

 Lagocephalui Jordan & Gilbert, Syn. Fish. N. A., 1883, 859 ilcevigatus, ifec). 



Type Tetrodon lagocephalus Linnaeus. 



Tbis genus is close to Sphceroides in all technical respects, but it seems 

 to be sufficiently distinguished by its nostrils and the form and develop- 

 ment of its fins. This increase in the number of fin-rays marks a slight 

 step in the direction of the genus Xenopterus { Chonerhinus). The species 

 reach a larger size than do tbose of our other genera, and the body is 

 more elongate in form. This is the only genus which is represented in 

 the fauna of Europe. 



The name of this genus offers no difficulty, Lagocephalus being prior 

 to Gastro])hysns, while Physogaster^ which has nearly the same date as 

 Lagocephalus^ is preoccupied. The characters assigned by Swainson to 

 Lagocephalus are valueless, but the indicated types belong to this group. 

 Only one American species is certainly referred to Lagocephalus. A 

 second one has been doubtfully noted as occurring in Brazil.* 



ANALYSIS OF SPECIES OF LAGOCEPHALUS. 



a. Belly covered with large, subequal, three-rooted spines, the body otherwise 

 smooth. Dorsal rays 14; anal rays 12. luterobital space flat, shorter than 

 snout, 1^ times diameter of eye; body elongate, its depth 4^ in length; tail 

 slender, a ridge of skin on its lower edge on each side. Olive-green above, 

 sides and below lustrous silver-white L^vigatus, 1. 



*Dr. Giinther mentious a specimen from Brazil, which he refers to a variety of 

 Lfigocephahin lunaris (Bloch & Schneider), a species otherwise only known from the 

 East Indian fauna. This .specimen is d<-scribed as having the interorbital space and 

 neck (jovered with spines (like tbe belly), the length of the head equal to its dis- 

 tance from the dorsal tin, and a broad dark band across the middle of the back. 



