286 
NAUTILOIDEA. 
? 1866. Nautilus Clementinus , Stoliczka, ibid. p. 20o. 
1874. Nautilus Clementinus^ Price, Quart. Jourii. Geol. Soc. vol. xxx. 
p. 363. 
1876, Nautilus Clementinus, Barrels, Recherches sur le Terrain Cr6- 
tac4 Superieur de I’Angleterre et dTrlande, p. 150. 
1878. Nautilus Clementinus, Barrels, M4m. sur le Terr. Crdt. des 
Ardennes, Ann. de la Sec. G^el. du Xerd, vel. v. pp. 270, 301. 
1878. Nautilus Clementinus, Linth, Beitriige zur geel. Karte der 
Schweiz, Lief. xiii. p. 21. 
? 1879. Nautilus Clementinus, H. B. Medlicett and W. T. Blanferd, 
Manual ef the Geelegy ef India, pt. i. p. 284. 
1881. Nautilus Clementinus, Etheridge, in Penning and Jukes-Brewne’s 
Geelegy of the Xeighhourhood of Cambridge (Mem. Geol. Surv. 
of Great Britain), Appendix A, p. 151. 
Sp, Char. Shell compressed-globose, marked in the young shell 
with fine striae, both longitudinal and transverse, forming a regular 
network : when the shell becomes older these stri® are replaced by 
slight longitudinal lines ; but these, at a still later stage of growth, 
completely disappear, the shell becoming quite smooth or marked 
only with faint lines of growth. The umbilicus is almost completely 
closed both in the young and in the adult shell. The aperture is 
higher than wide, a little flattened at the sides, but broadly rounded 
in front. The septa are moderately approximate, strongly bent 
forward in the region of the umbilicus, and nearly straight in 
passing over the periphery. There is a strong median (dorsal) lobe, 
which forms a very characteristic feature in the young of this species, 
and is best seen in detached septa ; this lobe disappears in the adult 
shell. The siphuncle is placed a little below the centre, varying in 
position from the lower third to the lower fourth of the septa. The 
test is very thick and is often preserved. 
Nemarks. This species differs from N. Bouchardianus, which is 
met with in the same beds, in its more compressed form, and in the 
different position of the siphuncle. Pictet ^ compares N. Clementinus 
with N. Montmolllni, Piet, et Camp., which, however, possesses an 
open umbilicus, much wider septa, and a siphuncle whose position 
is above, instead of below the centre. 
Mr. Blanford^ observes ' that “the Trichinopoly specimens [of 
N. Glementinus~\, which are not very numerous, exhibit nevertheless 
some variation in form, especially in the greater or less degree of 
flatness of the sides and ventral region.” Similar variations have 
been noticed by MM. Pictet and Campiche in their works on the 
Cretaceous fossils of Sainte-Croix, already cited. Mr. Blanford 
^ Loc. cit. p. 146. 
^ Loc. cit. p. 18. 
