408 On some Species of Jurassic &c. Nautili. 



the height of the whorl is 11 lines. Sutures forming an 

 acute, forwardly-directed lobe near the umbilicus, then bend- 

 ing backwards into a somewhat broader lobe, and again 

 directed forwards towards the periphery, in crossing which 

 they make a broad arch. There is a very distinct internal 

 (dorsal) lobe in young specimens. The siphuncle is a little 

 below the centre. The body-chamber and test are unknown. 



Remarks. This species is distinguished from Nautilus 

 franconicus by the form of its shell, which has a rounded 

 instead of a truncated periphery ; its siphuncle also is differ- 

 ently placed. There is no species in the Chalk of Europe 

 with which it may be compared. N. danicus has been recog- 

 nized by H. F. Blanford* in the upper part of the Arrialoor 

 Group (Cretaceous) of Southern India. Mr. Blanford found 

 that the only difference between the Indian specimens and 

 the figures of N. danicus given by Lyell in the Trans. Geol. 

 Soc. (loc. cit.) was " a somewhat greater compression of 

 form " in some of the former ; this he found, however, to be 

 a variable character in the Indian specimens. He remarks 

 that the very large size to which the Trichinopoly specimens 

 occasionally attain can scarcely be regarded as a specific 

 character. The internal lobe is present in young examples 

 of the Indian specimens, disappearing in older ones. In the 

 volume already quoted f Stoliczka has the following remarks 

 on the present species : — " So far as the existing figures of 

 N. danicus [Trans. Geol. Soc, loc. cit.'] allow an opinion to 

 be formed, the Indian fossil does not vary from the European, 

 except in the usually greater thickness of the whorls." The 

 following species from the Cretaceous rocks of Southern 

 India form a group of which N. danicus is the European 

 representative, viz. N. serpentinus, Blanford J, N. Forbesia- 

 nus, Blanford §, N. trichi?iopolitensis } Blanford ||. 



Horizon. Upper Chalk. 



Locality. Faxoe, Denmark. 



Tertiary. 

 12. Nautilus [Hercoglossa) Cassinianus, sp. no v. 

 [Aturia Cassiniana, Edwards, MS.] 



Sp. char. Shell compressed, with flattened sides and nar- 

 rowly rounded periphery. Greatest thickness in the region 



* Mem. Geol. Surv. India, Palasont. Iudica, 1861, series i. Cret. 

 Ceph. of Southern India, p. 24. 



t Mem. Geol. Surv. India, Palaeont. Indica, 1866, series iii. Cret. 

 Ceph. of Southern India, p. 208. 



\ Mem. Geol. Surv. India, Palseont. Indica, ser. i. 1861, p. 25, pi. xii. 

 figs. 1, 1 a ; ibid. ser. iii. 1866, p. 208, pi. xcii. tig-. 2. 

 °§ Ibid. p. 26, pi. xiii. 



|] Ibid. p. 37, pi. xxiii., pi. xxiv. figs. 1, 2; ibid. ser. iii. 1866, p. 212. 



