CARCHARIAS. 23 



brownish along the base of the subcaudal, lower margin broadly edged with 

 white; caudal tipped by a large spot of black in front of which is a transverse 

 band of white. 



Larger specimens brown on the back shading to white on the lower surfaces. 



The specimens at hand, from the Mediterranean Sea and from Japan, belong 

 to the species known to the French by the vernacular name "Perlon," first 

 described by Broussonet, 1780, afterward given the name "Squalus perlo" by 

 Bonnaterre, 1788, a year earlier than the designation Squalus cinereus by Gmelin, 

 1789. 



A closely allied species of this genus, very abundant in the formations of 

 the Upper Cretaceous, is that described by Agassiz, 1835, from the English 

 Chalk under the name Nolidanus microdon, Poissons Fossiles, 3, pi. 27, f. 1. 



Carcharidae. 



Body elongate, subfusiform, compressed. Head depressed, tapering. Tail 

 long, compressed, without lateral folds, vertebral axis of caudal nearly horizontal. 

 Nostrils transverse. Mouth large, greatly arched, with labial folds on the lower 

 jaws. Eyes small, without nictitating folds. Spiracles small. Gill openings 

 wide. Teeth subulate, slender, with two rooted bases. 



Snout short, mouth somewhat protractile 

 dorsals, ventrals and anal subequal 

 caudal pit present above 



subcaudal lobe produced .... Carcharias (page 23) 

 Snout much produced, mouth greatly protractile 

 dorsals smaller than ventrals and anal 

 caudal pit indistinct 



subcaudal lobe not produced . . Scapanorhynchus (page 28) 



Carcharias. 



Carcharias Rafinesque, 1810, Caratteri, p. 10. 



Triglochis Muller & Henle, 1837, Sitzb. Akad. wiss. Berlin, p. 113; Wiegm. arch., p. 396. 



Odonlaspis Agassiz, 1838, Rech. poisa. foss., Texte, p. 87; 1843, ibid., 3, p. 287, 306; Muller & Henle, 



loc. cit., p. 114; 1841, Plagios., p. 73. 

 Eugomphodus Gill, 1861, Proc. Acad. nat. sci. Phil., p. 60 extra. 



Body fusiform ; head depressed, tapering; snout short. Nostrils transverse. 

 Eyes without nictitating folds. Mouth large, arched forward. Teeth with 

 awl-shaped lanceolate cusp and two-rooted base, with or without denticles at 

 each side of the cusp. Spiracles small, behind the eyes. Gill openings wide, in 



