STOTIDANIDiE, 
15 7 
Suborder II. ASTEROSPONDYLI. 
Vertebrae, when fully developed, having the radiating calcified 
laminae predominating over the concentric laminae ( asterospondylic , 
Hasse). Specialization resulting in no marked depression of the 
body, and the pectoral fins never growing forwards towards the 
head; spiracles of small size, almost or quite absent in tire most 
specialized forms. Anal fin present. 
Division A .—A single dorsal fin present ; gill-clefts more 
than five in number. 
The following primitive family is provisionally placed here, its 
distinctive subordinal characters being not yet very evident, but its 
relationships being obviously closer with the Cestraciontidae than 
with any other hitherto recognized family. 
Family NOTIDANIDiE. 
Single dorsal fin, without spine, remote; caudal fin large. No 
nictitating membrane; gill-clefts 6-7; spiracles small. Teeth 
with sharply-pointed coronal cusps, several series simultaneously 
functional. 
Genus NOTIDANUS, Cuvier. 
[Regne Animal, vol. ii. 1817, p. 128.] 
Syn. Heptranchias , C. S. Rafinesque Schmalz, Caratt. Xuovi Gen. 
Anim. Sicilia, 1810, p. 13. 
Hexanchus, C. S. Rafinesque Schmalz, op. cit. p. 14. 
Monopterhinus , H. D. de Blainville, Bull. Soc. Philom. 1816, 
p. 121 (in part). 
Aellopos , L. Agassiz, Poiss. Foss. vol. iii. 1843, p. 376 (in part). 
Xiphodolamia , J. Leidy, Journ. Acad. Nat. Sci. Philad. [2] yol. viii. 
1877, p. 252. 
Body moderately elongated: mouth inferior; gill-openings six 
or seven, without flaps of skin. Principal teeth consisting of a 
series of compressed cusps fixed upon a long base; all the cusps 
inclined in one direction, the anterior larger than the others, with 
or without small denticles at its base in front. Anterior teeth of 
the upper jaw clustered, awl-shaped; a median symphysial series in 
