392 Messrs. Foord and Crick on new and 



subgenus Hercoglossa, and not to Aturia. It may here be 

 added that Conrad distinctly states in his description of 

 Hercoglossa* that the siphuncle is not funnel-shaped [as in 

 Aturia], but tubular. He includes in Hercoglossa the Aturia 

 Maihewsoni of Gabb f, though doubtfully, because Gabb did 

 not describe the character or position of the siphuncle in his 

 species, merely stating "siphuncle large." 



It is open to question whether Grypoceras, Hyatt J, should 

 not be merged in Hercoglossa ; we are inclined to the opinion 

 that it should. Thus the type species of the former [Nautilus 

 mesodiscus, Hauer§) is distinguished, according to Hyatt, 

 from that of the latter (N danicus, Schloth.) by the presence 

 of a " V-shaped " ventral lobe in the sutures and by a flat- 

 tening of the periphery " at some stage of growth." Now in 

 some species the ventral lobe, as, e.g., in the type, is perfectly 

 distinct, but in others, as, for instance, N. stranibergensis, 

 Oppel ||, it is so slightly indicated as to approach those species, 

 such as N. Oppeli, Zittel ^[, in which there is no such lobe. 

 In other species, again, the presence of the lobe is due, in part 

 at least, to the sulcation of the periphery. 



The flattening of the periphery mentioned by Hyatt as also 

 one of the characters of Grypoceras is not always accom- 

 panied by " V-shaped ventral lobes," Nautilus Picteti, Oppel, 

 having a flattened and sulcated periphery, but no ventral 

 lobe. The distinction therefore between Grypoceras and 

 Hercoglossa is very difficult to maintain. 



We include also in Hercoglossa the genus Enclimatoceras 

 of Hyatt **, type E. Ulrichi, White ft- 



Professor Dr. K. A. von Zittel J J retains the name Aganides, 

 Montfort, for Nautilus franconicus, Oppel, &c. ; but if the 

 type specimen of Montfort's genus came from Namur, as 

 stated by Montfort and afterwards by Sonnini§§, there is a 

 strong probability that it was a Goniatite, the rocks in that 



* Amer. Journ. of Concbology, 1806, vol. ii. no. 2, p. 101. 



t Geol. Surv. of California, Palaeont. 1804, vol. i. p. 59. 



% Proceed. Boston Soc. Nat. Hist. 1883, vol. xxii. p. 269. 



§ ' Die Ceplialopoden des Salzkammergutes,' 1846, p. 36, tab. x. figs. 4- 

 6. See also Mojsisovics, ' Das Gebirge urn Hallstatt,' 1873, p. 21, Taf. viii. 

 fig.l. 



|| 'Die Petrefactenkunde,' 1820, p. 83. 



*ff " Die Cepbalopoden der Stramberger Schichten," in Oppel and 

 Zittel's ' Palseontologiscke Mittlieilungen,' 1868, Band i. Abtb. ii. p. 42, 

 tab. ii. figs. 8-11. 



** Proceed. Boston Soc. Nat. Hist. 1883, vol. xxii. p. 270. 



|f Bull. United States Geol. Surv. 1884, vol. i. p. 17, pis. vii., viii., ix. 



XX Handbuch der Palaeontology, Band ii. p. 383 (1884). 



§§ Hist. Nat. des Mollusques (Montfort's ed. of Sonniui's ' Suite a 

 Button '), torn. iv. 1799 (An x.), p. 253, pi. xlviii. fig. 1. 



I 



