Jordan and Evermann. Fishes of North America. 2291 



Family CXCIII. CHIASMODONTIDJE. 

 (THE BLACK SWALLOWERS.) 



Body elongate, subcylindrical, or slightly tapering; head subconic. 

 Skin naked; lateral line continuous, placed low; 2 dorsal fins, the first 

 rather short, of slender spines, the second dorsal and anal long; ventrals 

 normal, thoracic, inserted before pectorals, the rays I, 5 ; pectorals long and 

 narrow; mouth very deeply cleft, reaching beyond tbe eyes, with numer- 

 ous long, sharp, movable teeth, the anterior canines movable; teeth on 

 palatines; upper jaw not protractile, the maxillary produced backward. 

 Opercular apparatus very oblique and reduced; no spines or cirri on head; 

 caudal fin forked. Genera 2; species 2; deep-sea fishes, notable for the 

 sharp teeth and for the extensible stomach. (ChiasmodontidcB, Gill, in Jor- 

 dan & Gilbert, Synopsis, 964, 1883.) 



a. Jaws with some of the anterior canines extremely long and movable, the 2 anterior 



.^ crossing each other; lower jaw projecting. CHIASMODON, 847. 



aa. Jaws with slender, close-set teeth, none of them greatly produced ; lower jaw not 



prominent. PsEUDOSCOPELUS, 848. 



847. CHIASMODON, Johnson. 

 (BLACK SWALLOWERS.) 



Chiatmodon, JOHNSON, Proc. Zool. Soc. London 1863, 408 (niger). 

 Chiasmodus, GUNTHER, change of spelling. 



Body elongate, compressed, and tapering posteriorly, naked; belly pend- 

 ent, its walls membranaceous, capable of great dilation. Mouth very 

 large; lower jaw longer than upper; each jaw with 2 series of large, 

 pointed teeth, some of the anterior being very large and movable; vomer- 

 ine teeth none ; palatines with teeth similar to those in the jaws. Gills 4. 

 No pseudobranchise. Gill openings very wide, the membranes joined to 

 the isthmus for a short distance. Dorsal fins 2; anal single; ventrals 

 inserted below pectorals, each of 5 soft rays. Tail truncate at base of 

 caudal. Caudal forked, free from dorsal and anal. Singular fishes of the 

 deep sea, remarkable for their ability to swallow fishes of many times 

 their own size by means of the great distensibility of the walls of the 

 body, (xi'adjua, a mark of the form of the letter #; 6d ov$, tooth; the 2 

 anterior canines crossing each other when depressed.) 



2629. CHIASMODON NIGER, Johnson. 



Head 3. D. XI-28 ; A. 27 ; P. 13 ; V. 5. Head compressed, elongate, the 

 crown flat, its depth less than | its length ; maxillary reaching angle of 

 preopercle; both jaws armed with long, pointed, wide-set teeth, nearly 

 all of which are movable; 2 anterior teeth of upper jaw very long, cross- 

 ing each other when depressed; 3 anterior pairs of teeth in lower jaw 



