64 Chapman and Pritcltard : 



the symphysial facette. The width of the la;tter is 8 nun. near 

 the posterior margin. A narrow elevated ridge runs along the 

 symphj^sial facette about 5 mm. from the margin, making an 

 angle of about 30 deg. with the posterior layer. The tritors 

 consist of very coarsely tubulated material, a.nd in this speci- 

 men have been almost entirely weathered out, only a thin layer 

 remaining, but sufficient t > show the presence of three very 

 long, narrow tritors on the posterior portion of the tooth. 



Dimensions. — Heiyht, 30.5 mm.; greatest thickness, 16 mm. 



Locality and Horizon. — Table Cape, Tasmania. From the 

 "Turritella beds." Jan Jukian. Tasmanian Museum Collection, 

 Hobart. 



Observations. — The above species shows a striking similarity 

 in its general characters to Ischyodus egertoni. Bucklandi from 

 the British Jurassic, but is much' narrower and more elongate, 

 with long narrow tritors showing a more marked parallelism. 



The genus Ischyodus ha's; been previously recorded from the 

 Tertiary rocks of Amuri Bluff, New Zealand, and identified with 

 Agasisiz's I. brevirostris by E. T. Newton.- The latter species 

 belongs to the Lower and Upper Cretaceous of England. It 

 is unfortunate that a reference to the Amuri Bluff deposits as 

 Greensand'^ should have been made and pei'petuated. consider- 

 ing that the faima is so distinctly tertiary. Subsequent to 

 Newton's description of the New Zealand specimen, three others 

 have been recorded under the same specific name by J. W. 

 Davis, from Amuri Bluff."* It is just possible, however, that 

 since these speciniens are more or less fragmentary, further 

 material may show the New Zealand form to be aj distinct 

 species. 



With regard to the name I. brevirostris, A. S. Woodward has 

 already shown' that I. thurmauni, Pictet and Campiche. has 

 priority over it. 



1 Chimaera ei^ertonii, Buckland. Proc. Geol. Soc. Lond., vol. ii., 1S35, p. 206. 

 Chiinoera (Ischyodus) egertoni, Agassiz. Poiss. Foss., vol. iii., 1S43, p. 340, xl.c, figs. 1-10. 



2 Quart. Jour. Geol. Soc, vol. xxxii., 1876, p. 320, pi. xxi., flg. a. 



3 Hector, Handbook of N. Zealand, 1883, p. 31 (referred to as Lower Greensand).— 

 Newton, Q.J.G.S., vol. xxxii., 1876, p. 326 (Lower Greensand).- Davis, Trans. R. Dubl. 

 Soc, vol. iv., ser. 2, 1888, p. 42 (Cretaceo-tertiary). Sniitli Woodward, Cat. Foss. Fishes, 

 Brit. Mus., pt. ii., p. 68 (Greensand). 



4 Trans. R. Dubl. Soc, vol. iv., ser. ?, 1S8S, p. ii, pi. \ ii.. tigs. 10-13. 



5 Cat. Fossil Fishes, Brit. Mus., pt. ii., 18l»l, \>. iu. 



