208 THE PLAGIOSTOMIA. 



Teeth unlike in the two jaws: upper awl-shaped, raptorial; lower compressed, 

 smooth on the edges, sectorial, more or less oblique. Two small dorsal fins, 

 with the spine shortly exposed. Caudal well developed, vertebral axis raised 

 backward, subcaudal lobe rather weak. 



Spine of first dorsal more than halfway from end of snout to caudal, not reached 

 by the pectoral 

 cusps of lower teeth nearly erect. 

 dorsal spines slightly projecting 



base of first dorsal, without spine, 1 of interdorsal space 



ringens (page 208) 

 Spine of first dorsal about halfway from end of snout to caudal, not reached by 

 the pectoral 



base of first dorsal less than g of interdorsal space 



squamuhsus (page 209) 

 Spine of first dorsal less than halfway from end of snout to caudal, 

 cusps of lower teeth oblique 



dorsal spines somewhat projecting, nearly reached by the pectorals 

 base of first dorsal more than 5 of interdorsal space 



plunketi (page 210) 

 dorsal spines strongly projecting, first dorsal reached by pectorals 

 base of first dorsal f of interdorsal space maeracanthus (page 210) 



SCYMNODON RINGENS. 



Scymnodon rigens Bocage & Capello, 1864, Diag. fam. Squat, p. 3 extra. 



Scymnodon ringens Bocage & Capello, 1864, Proc. Zool. soc. London, p. 263, f. 5; 1866, Plagios., 



p. 32, pi. 1, f. 1; Capello, 1870, Jor. Acad. sci. Lisboa, 2, p. 145; Regan, 190S, Ann. mag. nat. 



hist.., ser. 8, 2, p. 48. 

 Centrophorus ringens Gunth., 1870, Cat. fishes Brit, mus., 8, p. 423; Sim, 1902, Ann. Scott, nat. hist., 



11, p. 13. 

 Centroscymnus obscurus Vaillant, 1888, Travailleur et Talisman, Poissons, p. 67, pi. 2, f. 2. 



Snout large, short, subconic, length from the end to the eye about half of 

 that from the same point to the spiracle, perhaps a little less; mouth wide, with 

 a deep groove at each angle, and with labial folds; nostrils oblique, at the end of 

 the anterior third of the preoral length. Upper teeth raptorial, subulate; lower 

 compressed, sectorial, with a quadrangular base on which is a triangular, smooth- 

 edged, more or less oblique cusp. Spiracle large, nearly parallel with the upper 

 surface of the head. Pectorals medium, oblong, rounded. Dorsal spines 

 exposed at the point, that of the first dorsal about midway from the origins of 



