^^AUTILID^. 
183 
Mojsisovics further remarks that the majority of the Mediterranean 
Trias Nautili are distinguished from the Palaeozoic Nautili by the 
presence of an inner lobe. This feature is preserved in a great 
number of Post-Triassic forms up to the present time, Nautilus 
pompilius having it in the young shell. 
Pseudotiautilus, Meek\ which has for its type Nautilus Geinitzi, 
Oppel differs from Hercoglossa “ in having the septa also provided 
with a well-defined peripheral and antiperipheral lobe, and the 
siphuncle placed near the outer margin.” 
Meek expresses the opinion that Hercoglossa “ forms a transition 
from Nautilus proper to Aturia ; that is, it agrees exactly with the 
former in all respects, excepting in the lobed character of its septa, 
in which, as well as in form, it agrees still more nearly with the 
latter ; but it nevertheless differs from Aturia in having its siphuncle 
cylindrical and more nearly central, as in Nautilus^ and not large 
and funnel-shaped,” and, ho might have added, close to the internal 
margin. 
It certainly appears that we have in Hercoglossa a group of forms 
whose septal characters differentiate them from the typical Nautili, 
though it must be admitted, as Meek has pointed out, that there are 
many intermediate gradations to be found among extinct species 
{Nautilus Calloviensis, e. g. fig. 55, p. 234) presenting septa of the 
Hercoglossa type, which show that the latter can hardly be regarded 
as a distinct genus. 
Professor Dr. K. A. von ZitteP retains the name Aganides, 
Montfort, for Nautilus Fmnconicus, 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 Gouiatite, the rocks in that neighbourhood being of 
Carboniferous age. It is true that the siphuncle is represented in 
8onnini’s figure as nearly central, but this might have been a mistake 
on the part of the artist. It would, at any rate, be impossible to 
1 United States Geol, Surv. Terr. 1876, vol. ix. p. 491. Meek draws attention 
in a footnote to the very curious and interesting intermediate characters between 
the Nautilus and Goniatites groups presented by Pseudonautilus. His remarks 
have already been quoted in this Catalogue (Pt. I., Introd. footnote, p. xviii). 
^ Zeitschr. der deutsch. geol. Gesell. 1865, Band xvii. p. 546. See also “ Die 
Cephalopoden der Stramberger Schichten,” in Oppel and Zittel’s Palseontologische 
Mittheilungen, Band ii. Abth. i. p. 45, Taf. ii. ff. 1-7. Nautilus aturioides, Pictet 
(Melanges Paleontologiques, 1 867, tom. i. livr. ii. p. 63, pi. xi. ff. 1, 2), is regarded 
by Zittel (Die Ceph. d. Stramberger Schicht. p. 45) as identical with N. Geinitzi. 
^ Handbuch der Palasontologie, Band ii. p. 383 (1884). 
Hist. Nat. des Mollusques (Montfort’s ed. of Sonnini’s ‘ Suite a Buffon ’), 
tom. iv. 1799 (An. x.), p. 253, pi. xlviii. f. 1. 
