Jordan and Evermann. Fishes of North America. 975 



spines upon the dentary and articular elements. Vertebrae 10 + 36 = 46. 

 Anterior neural spine not excavated, being lofty and smooth ; the 5 that 

 follow are short and inclined backward ; remaining ones slender, as also 

 their hiumapophyses ; last vertebra) without lateral spines. Pleurapop- 

 hyses inconspicuous, feebly developed, of much the same size and shape as 

 the epipleurals ; but one pseudo-interneural spine in front of the one that 

 supports the first dorsal fin ray. (Poey.) A single specimen of this 

 remarkable fish was obtained by Poey at Cuba, in 1872. (Name a Latin 

 diminutive of ft/xixiov, arm, from the small pectoral.) 



Grammicolepis brachiusculus, POEY, Anal. Soc. Esp. Hist. Nat., n, 1873, Cuba; SHUFELDT, Journal 

 Morphology, n, 1888, 271, with 13 figures; GOODE & BEAN, Oceanic Tchth., 218, fig. 221, 1895. 



In a natural arrangement the Grammicolepididw should apparently be 

 followed by the Ephippidiv, and these in turn by the Chwtodontidcv and their 

 allies, from which are derived the long series of aberrant or degenerate 

 forms known as Plectognathi. The needs of a linear arrangement make it 

 desirable to interrupt the series here to give place to the Tetragonuridw 

 and other aberrant forms which may be allied to the Scombridce, and also 

 to the long series of Percoidea, which are also very closely allied to the 

 mackerel-like fishes. When the Percoid series is finished we shall revert 

 to these remote branches from the Mackerel stem, if such the Chwtodon- 

 tidce and the Plectognaths should prove to be. 



Family CXXXVIII. TETRAGONURID.E. 

 (THE SQUARE TAILS.) 



Body long, slender, plump, not compressed, covered with hard, ciliated, 

 grooved scales, which are very adherent. Lateral line single, straightish. 

 Head scaly ; opercles entire ; eye large : mouth short, oblique, the jaws 

 box-like, armed with one series of close set, comb-like teeth; teeth on 

 palate. Dorsal divided, short and low; spines about 15; soft rays 

 few ; anal very small, its spines indistinct ; caudal peduncle long, rather 

 slender, with cartilaginous expansions at the base of caudal; caudal 

 rather small, forked; ventrals small, subabdominal, placed below middle 

 of pectoral, I, 5; pectorals short; no air bladder. Atlantic; probably 

 but one species ; in deep water, apparently rare. The relationships of the 

 group are doubtful. Lowe places it among the mackerels, Giinther near 

 the Mugilidce. It seems remotely allied to Bramidce and other Scombroid 

 forms, but it forms a distinct group without near relatives. (Tetragon- 

 urina, Giinther, Cat., in, 407, 1861.) 



447. TETRAGONURUS, Risso. 



Tetragonurus, Risso, Ichth. Nice, 347 ,.1810, (cuvieri). 



Ctenodax, MACLEAY, Proc. Linn Soc. N. S. Wales, 1885, 718, (wilkinsoni). 



Characters of the genus included above, (rerpayuvos , square ; ovpd, tail; 

 square-tailed, from the form of the caudal peduncle.; 



