A. Smith Woodward — On the Genus Notidanus. 215 



very much more minute. Behind the principal cone, which is 

 scarcely more rohust than that immediately following, there are 

 ranged three other cones, of gradually diminishing size ; and posterior 

 to these a minute denticulation is visible. 



In the upper tooth (Fig. 17) the principal cone appears more 

 definitely contrasted with the others. In front there are two distinct 

 denticles, the first being three times the size of the second, and the 

 principal cone itself is placed almost vertically with respect to the 

 base-line of the crown, although its anterior edge has a much less 

 abrupt slope than the posterior. Behind this, there are three other 

 cones rapidly decreasing in dimensions ; the first, somewhat inclined 

 backwards and three-fourths the size of the principal cone ; the 

 second, backwardly directed at a corresponding angle, but only 

 about one-third as large as the first; and the third, a minute, broad 

 acuminate denticle. Though now imperfectly shown, the base-line 

 of the crown was obviously arched, and the remains of the root 

 indicate the usual configuration and robust proportions of an upper 

 tooth. 



On considering this assemblage of characters, the substitution of 

 distinct denticles for the ordinary serrations on the anterior edge of 

 the principal cone in the lower tooth, is obviously the most striking 

 feature ; and hence it is proposed to distinguish the present modifi- 

 cation under the specific name of N. dentatus. The only other fossil 

 Notidanus that exhibits this peculiarity is the very rare N. pectinatus 

 from the English Chalk, but this is a much smaller species, and 

 differs in possessing a longer series of cones behind the principal. 

 Among existing forms, however, one appears to be remarkable for 

 its possession of the very same character. 1 This is the little N. 

 pectorosus from the seas off the Patagonian coast, and Mr. Garman's 

 description 2 of the lower tooth of this form agrees almost precisely 

 with the particulars given above ; he states that each tooth " has one 

 to two small, followed by four moderate-sized, cusps, the anterior of 

 the four being little if any longer than the other three ; and, in cases, 

 there is also a small cusp on the posterior portion of the base." 

 Indeed, in the absence of figures, IV. dentatus can only be distin- 

 guished from N. pectorosus by the presence of one more anterior 

 denticle in its teeth, and by its relatively gigantic size — for the 

 Patagonian species is only 16 inches in total length. 



If subsequent researches tend to substantiate the latter statement, 

 the fact becomes of unusual interest, since it was from the same 

 deposit at Amuri Bluff that Mr. E. T. Newton, a few years ago, 3 

 made known a tooth of Callorhynchus, differing only in minor points 

 from G. antarcticus of the present southern seas. This living 

 Chimaeroid ranges through the same ichthyological province as Mr. 

 Garman's new species of Notidanus, and the association of two extinct 



1 The lower teeth of 2V. einereus also exhibit some approach to this character. 



2 S. Garman, " A species of Heptranchias supposed t to be new," Bull. Essex 

 Institute, vol. xvi. (1884), pp. 56, 57. 



3 E. T. Newton, " On Two Chimajroid Jaws from the Lower Greensand of New 

 Zealand," Q,. J. Geol. Soc. vol. xxxii. (1876), pp. 329, 330, pi. xxi. figs. 6—9. 



