SUPPLEMENT.— DELTOTOCEEAS. cxix 



Note. — The inner whorls of the umbilicus show coarse costse. 



Distinction. — From Deltoid, astrictum, earlier failure of costae, slightly more 

 compressed whorls, with less deltoid cross section. 



Remarks. — In the two figured examples the suture lines, obscurely seen , appear 

 to be sublongi-subangustilobate. The radial line on the smaller specimen agrees 

 with this genus; in the larger one it cannot be satisfactorily followed. The cross 

 section in the larger example agrees with that of the genus — gradual decline of 

 the deltoid figure by compression around umbilicus would be expected. That 

 the two examples are specifically identical might be questioned. 



Date of Existence. — Discitse hemera, presumably. 



Alticarinate. 

 The carina is a very marked feature. 



XLIX. Genus — Deltotoceras, 1 S. Buchnan. 



(Type : Deltotoceras cuneatwm, sp. n.) 

 1902. Deltoceras, Emend. Amm. Norn., p. 3. 



Definition. — -Platygyral, in cross section deltoid; angustumbilicate ; subdensi- 

 septate, longi-subangustilobate ; laterally perflexiradiate, peripherally acutanguli- 

 radiate, tabulate, alticarinate (septicarinate). (Radial line fig. 83, p. clxv.) 



Remarks. — Technical terms fail in the definition, the thickness of the whorls 

 being so different on inner and outer areas. They are convergent-sided, with a 

 deltoid figure. In the genotype the carina is distinctly septate; but as I have not 

 observed this character in other species of this or of allied genera, it may be doubted 

 if it be a character of generic distinction. 



The species of this genus are clearly allied to Deltoidoceras, but rostration 

 has been carried further, and the whorl thickness is greater. 



Distinction. — From Deltoidoceras, stouter whorls with more pronounced deltoid 

 section, a larger and more developed carina, radial line with more peripheral 

 projection. 



Note. — The name first proposed was occupied. 



Crassicarinate. 

 1. Septicarinate. 



1. Deltotoceeas cuneatum, S. Buckman. Suppl., Plate XVI, figs. 7 — !». 



Remarks. — The inner whorls of the figured specimen give evidence of some- 

 what coarse costae — an ornament similar to, but perhaps more pronounced 

 1 AeXrwroc, delta-shaped, as the cross section is. 



