NAFT1L1D.I:. 
285 
Sowerby describes his species as “ plain.” Sowerby’s specimen 
being a cast, may not have exhibited any distinct ribbing, which 
might nevertheless have been faintly visible, as is found to be the 
case in some weathered specimens. However this may be, the 
straight and rather widely separated sutures and the general form 
of the shell in JT. semiundatus are features in which it resembles 
X simplex, so far as may be judged from the figure and description 
I of the latter. Unfortunately, the siphuncle has not been seen iu 
N. semiundatiis, and therefore it cannot be invoked in aid of this 
I comparison. Its position in simplex is described as “nearest to 
" the inner edge of the septum.”] 
r 
Nautilus Clementinus, d'Orbiguy. 
! 1840. Nautilus Clementinus, d'Orbigny, Paleontologie Fran 9 aise (Ter- 
(j rains Cretaces), vol. i. p. 77, pi. xiii. bis. 
? 1841. Nautilus Clementinus, Duval-Joiive, Belemn. des Terrains Cr4- 
' taces, p. 9. 
,| 1842. Nautilus Clementinus, Leymerie, Hem. Soc. Geol. de France, 
j vol. V. pt. i. p. 31. 
184G. Nautilus Clementinus? , Forbes, Trans. Geol. Soc. ser. ii. vol. vii. 
p. 98. 
1846. Nautilus Clementinus, Leymerie, Stati?tique Geologique et 
' Mineralogiqiie du Departement de I’Aube, p. 165. 
I 1850. Nautilus Clementinus, d’Orbigny, Prodrome de Paleontologie 
Stratigrapbique, vol. ii. p. 122. 
t 1850. Nautilus Indicus, d’Orbigny, ibid. vol. ii. p. 211. 
I 1852. Nautilus Clementinus, Giebel, Fauna der Vorwelt, Band iii. 
Abth. i. p. 148. 
' 1853. Nautilus Clementinus, Cotteau, Molliisques Fossiles de I’Yonne, 
• P-6. 
1853. Nautilus Clementinus, Studer, Geologie der Schweiz, vol. ii. p. 83. 
{ 1854. Nautilus Clementinus, Morris, Catalogue of British Fossils, 2nd 
ed. p. 306. 
1854. Nautilus Clementinus, lienevier, Perte-du-Bhone, p. 36. 
(■ 1858. Nautilus Clementinus, Ooster, Catalogue des Cephalopodes Fos- 
siles des Alpes Suisses, pt. iii. p. 13. 
' 18-59. Nautilus Clementinus, Pictet et Campiche, Description des Fos- 
' ; siles des Environs de Sainte-Croix (Paleontologie Suisse), ser. ii. 
j, pt. i. livr. vii. p. 144, pi. xix. if. 1-5. 
! 1861. Nautilus Clementinus, Reynes, Etudes sur la Synchronisme et 
I la Delimitation des Terrains Cretaces du Sud-Est de la France, 
j p. 40. 
P1861. Nautilus Clementinus, Blanford, Mem. Geol. Surv. India — 
Palaeont. Indica — i. The Fossil Cephalopoda of the Cretaceous 
Rocks of Southern India, p. 17, pi. vi. pi. vii. If. 1, 1 a, 2. 
I 
