4 
NAUTILOIDEA. 
F. Noetling, in an elaborate paper, “ Ueber Lituites lituus, 
Montfort,” ^ discusses the subject of the classification and develop- 
ment of Lituites in an exhaustive manner. He concludes his 
memoir by suggesting that the shell must at successive epochs have 
passed through the following phases : — (1) The Nautilus-'^idigQ, in 
which the shell resembled a very e volute ws-shell ; the aperture 
two-lobed (judging by the lines of growth), with deep, narrow 
ventral sinus, broad, not very high lappets at the side, and shallow 
dorsal sinus ; (2) the Imperfecti-'^idige, which was entered upon 
immediately after the shell had ceased to be coiled, and included 
only a short bent portion ; (3) the Per/ec^i-Stage, which included the 
continuation of the shell in a straight direction up to the aperture. 
These points will be made clearer by referring to the illustration on 
p. 2 (fig. 1), which shows that the Imperfecti-^idi^e, is, after all, but 
very slightly marked off from the Perfecti-^idige. jN’oetling finds in 
the development of Lituites lituus indications of the descent of the 
genus Lituites from Nautilus-]j^Q ancestors, though nothing is yet 
known of the parent form. 
In a later publication ^ he institutes the family Lituidce for the 
two genera Lituites and Ancistroceras, the latter of which supersedes 
Strombolituites of Eemele ^ Hyatt ^ refers only very briefly to 
Lituites, which he does not define, but remarks that the genus 
appears to be represented in the Calciferous of this country [N. 
America] by Lituites Farnsworthi, Bill., Pal. Foss. vol. i. 1861, 
p. 21, fig. 24, and L. imperator. Bill., ibid. p. 23 . . .” Perhaps 
also “ Gyroceras {Lituites) magnijicum, Billings might be added 
to these, but its characters have not been clearly made out. If it 
be a Lituites it is the giant of its tribe, the discoidal spire being 
“ about 8 inches in diameter, the produced free extremity at least 
20 inches in length in the fuU-grown individuals.” These dimen- 
sions throw the Swedish and German specimens completely into the 
shade. The Lituites angulatus of Saemann is relegated by Hyatt 
to the genus Trocholites, in which association it will be found in 
this Catalogue. 
^ Zeitschrift der Deutsch. geol. GeselL, Band xxxiv. 1882, Heft i. pp. 156-193, 
Taf. X., xi. 
^ Jahrb. der Konigl. Preuss. geol. Landesanst. und Bergakad. zu Berlin f. d. 
Jahr 1883 (1884); “ Beitrage zur Keuntn. der Cephalopoden aus Silurgescli. 
der ProTinz Ost-Preussen,” p. 101. 
3 Zeitscbr. der Deutsch. geol. GeselL, Band xxxiii. 1881, p. 192. 
“ Genera of Fossil Cephalopods,” Proc. Boston Soc. Nat. Hist. vol. xxii. 
1883, p. 267 (footnote). 
^ Geol. Surv. Canada, Eep. of Progress, 1853-1856 (1857), p. 307. 
