262 Avnah of the South African Museum. 



B. NAUTILOIDEA. 



GEN. EUTREPHOCERAS, Hyatt. 



23. EUTREPHOCERAS aff. DEKAYI, Morton Sp. 



1907. Nautilus dekayl (Morton). Stuart- Weller, Report on Cret. 



Pal. of New Jersey, vol. iv (Pal. Ser.), Geol. Surv., N.J., p. 817, 



pi. e., figs. 2-5. 

 1910. Nautilus dekay't (Morton), Spengler. " Untersuch. u. d.Siidind. 



Kreideform. Pt. iv : Die Nautil. uud Bel. d. Trichinopoly 



Distr.," Beitr. x. Pal. und Geol. Ost.-TJng., vol. xxiii, pt. iii, 



p. 137. 



A small and poorly preserved specimen (No. 2751), of a little over 

 40 mm. in diameter, and of equal thickness, seems to agree with the 

 typical figures cited above, and with specimens of this form from the 

 Fort Pierre Shale, Black Hills, South Dakota, U.S.A., in the writer's 

 collection. Since, however, the present example is somewhat crushed, 

 so that the original shape of the whorl-section cannot accurately be 

 determined, the specific identification must remain doubtful. 



The position of the siphuucle (centran) corresponds with that shown 

 in Fig. 4 of the reference given above, and not with that of fig. 1 a in 

 Meek* (dorsocentran). Spengler gives the thickness as 90-100 per 

 cent, (typically 92 per cent.), which agrees with that of the specimen 

 hei*e described. There does not appear to be an annular lobe. 



Eiitrepliocems ovoideus, G. C. Crick sp.,t probably an older 

 (Cenomanian) species, has a more elevated, less depressed whorl 

 section. Nautilus \_Cymatoceras ?] occlusus, G. C. Crick, + has a similar 

 globose, though less depressed, whorl-shape, but the position of the 

 siphuucle is centroventran, and there is an annular lobe at least in 

 the voung. Since the Senonian also occurs at the North-West end 



. o 



of False Bay, it is impossible to state whether the six examples 

 described by Crick are all of the same (Ceuomauian) age, or even 

 whether they are identical or co-generic, without breaking them up. 

 The Antarctic example of Nautilus blanfonlianus, Kilian and Reboul, 



* " Report Invertebr. Cret. and Tert. Foss. Up. Missouri Country," in 

 Hayden, ' U.S. Geol. Surv. of Ten-it.,' vol. ix (1876), p. 496, pi. xxvii. 



f Loc. cit. (1907), p. 222, B.M., No. C18253-6. 



t Ibid., p. 224, B.M., No. C18257-62. 



" Les Ceph. Neocret. d. lies Seymour et Snow Hill," ' Wiss. Ergeb. Sehwed. 

 Sudpol. Exped.,' vol. iii, pt. vi (1909), p. 8, pi. i, figs. 1 and 2. 



