Fishes of the Western North Atlantic 'jc) 



Notidanus Cuvier, Regne Anim., 2, 1817: 128; type species, Squalus griseus Bonnaterre, 1788, designated by 



Jordan, Genera Fish., I, 1 91 7: 97. 

 NotiJamus Miinster, Beitr. Petrefak., 5, 1842: 66; evident misspelling for Notidanus Cuvier, 1 81 7. 

 Hexancus L. Agassiz, Nomencl. Zool. Index, 1846: 181 ; equivalent to Hexanchus Rafinesque, 1810. 



Generic Characters. Six gill openings, decreasing in length from front to rear; snout 

 short, rounded; mouth very large, mostly lateral; lower labial furrow well developed; 

 upper lip widely expanded posteriorly; spiracles small, situated far behind eye; fins of 

 moderate size; anterior upper teeth slender, pointed; anterior lower teeth broad, quad- 

 rate; no median upper tooth; lower median tooth present or absent. Characters otherwise 

 those of the family and suborder. 



Range. Both sides of North Atlantic, Mediterranean, Argentina, southern Indian 

 Ocean, Island of Reunion, Natal and Agulhas Bank, Japan, west coasts of North and South 

 America. All known representatives of the genus appear to belong to a single wide-ranging 

 species. 



Fossil Teeth. Middle Jurassic to Pliocene, Europe; Upper Cretaceous, western Asia, 

 New Zealand, Madagascar; Upper Cretaceous to Oligocene, South America; Eocene, 

 Africa; Miocene, North America. 



Species. The representatives of this genus from diflFerent seas resemble one another 

 closely. But opinions have differed as to whether H. corinus Jordan and Gilbert' of the 

 Pacific coast of the United States is separable from the well known Six-gilled Shark 

 {griseus) of Europe. Supposedly, corinus is set apart from griseus by the fact that its 

 lower teeth other than the median are finely serrate along their inner edges. Actually, 

 however, no diflFerence exists in this respect between the populations of the two geo- 

 graphic regions in question, for the lower teeth of the European griseus were long ago 

 excellently pictured' and described* as having finely serrate inner edges, although this 

 fact seems to have been overlooked in some of the more recent accounts." On the other 

 hand, it is expressly stated in the original account of corinus^ that in a small specimen 

 from Puget Sound the lower teeth were smooth-edged, as they are also in a 2^ -foot 

 griseus from the Mediterranean that we have examined;^ and our comparison of the latter 

 with a four-foot specimen from Puget Sound reveals no significant difference in any other 

 respect. We therefore follow Regan^ and Fowler" in referring corinus, as well as the 

 Japanese Hexanchus, to griseus. There is nothing in the descriptions or obviously general- 

 ized illustration to suggest otherwise for the Chilean edulis.^" 



2. Proc. U.S. nat. Mus., 3, 1880: 352. 3. L. Agassiz, Poiss. Foss., 3, 1835; pi. e, fig. 2-4. 



4. Miiller and Henle, Plagiost., 1841 : 81. 



5. Garman (Mem. Harv. Mus. comp. Zool., 36, 1913: 17), for example, desoribes them without qualifications as 

 smooth-edged, and Rey (Fauna Iberica Peces, /, 1928: fig. 83) so pictures them. 



6. Jordan and Gilbert, Proc. U.S. nat. Mus., 5, 1880: 352. 



7. Similarly, the lower teeth are smooth-edged in a 429-mm. specimen from Cuba; the first large lower tooth is 

 serrate but the others smooth in one of about five feet ; all the large lateral lower teeth are more or less serrate 

 along their inner margins in one of 1 1 feet (see Study Material, p. 80) . 



8. Ann. Mag. nat. Hist., (7) 16, 1905: 57. 9. Bull. U.S. nat. Mus., 100 (/j), 1941: 57- 

 10. Perez-Canto, Estud. Escual. Chile, 1886; 8; Philippi, An. Univ. Chile, 71, 1887: 554, pi. 6, fig. i. 



