SCOLIODON. 109 



SCOLIODON. 



Scoliodon Muller & Henle, 1837, Sitzb. Akad. wiss. Berlin, p. 114; Wiegrn. arch., p. 397. 

 Scoliodon and Aprionodon Gill, 1861, Proc. Acad. nat. sci. Phil., p. 59 extra. 



Body compressed; head depressed, snout elongate, blunt. Mouth in- 

 ferior, greatly arched, with short labial folds at the angles. Teeth alike in the 

 two jaws, sectorial, more or less smooth on the edges, broad based, with a triangu- 

 lar cusp that is inclined outward over a notch above the base on the outer edge; 

 a median upper tooth, and two symphyseal teeth in the lower series, smaller in 

 some species. Nictitating membrane well developed. Caudal pits distinct; 

 subcaudal lobe prominent. Scales minute, with three to five keels. 



Of general distribution and fossil in Lower Eocene and later. 



Base of the anal more than twice the length of that of the second dorsal 

 labial folds short, on the lower jaws, not on the upper 



sorrakowah (page 110) 

 Base of anal not more than twice that of second dorsal 



labial folds short, on the lower jaws, not on the upper palasorrah (page 111) 

 labial folds in the angles 



length of snout nearly equal the distance from eye to pectoral 



dumirilii (page 111) 

 labial folds in the angles and slightly on the lower jaws 



distance between outer angles of nostrils and between them and end of 

 snout about equal 

 anal and second dorsal unequal, latter posterior 



walbeehmi (page 112) 

 anal and second dorsal subequal opposed porosus (page 112) 



labial folds on both jaws, hardly 5 the length of the jaws 



snout pointed, length from nostrils nearly equal the distance between 



their outer angles lalandii (page 113) 



labial folds on both jaws, about \ length of jaws 



snout rather pointed, length from nostrils about equal distance between 



their outer angles longurio (page 114) 



labial folds on both jaws short, less than i length of jaws 

 snout broadly rounded 



length from the nostrils much less than distance between their 

 outer angles terrae novae (page 115) 



