NAUTTLID-15. 
253 
front side and sloping behind, thus forming a series of steps on the 
surface ; the edge of the umbilicus is angular or raised into a slight 
keel. The longitudinal ribs are very prominent in some specimens, 
but can hardly be discerned in others : but the species can always 
be distinguished by the form of the ribs, the deep and angular 
umbilicus.” (^Sharpe.) 
RemarTcs. The sculpture, so well described by Sharpe, as well as 
its more inflated form, distinguishes this species from N. e.xpansus, 
Sow., which it resembles in its angular umbilicus. From the other 
transversely ridged species, such as N. elegans and N. radiatus, it 
is distinguished also by its umbilicus, as well as by the longitudinal 
ridges which cross the transverse ones and impart a reticulated 
aspect to the surface of the test. The longitudinal ridges are only 
seen in tolerably well-preserved specimens, such as those numbered 
83677 and C. 2249 in the Collection ; there is no trace of them in 
most casts. 
This species is very abundant in the Chalk Marl of England 
(Wiltshire especially), and it is also common in the Craie Chloritee 
of the neighbourhood of Rouen (8einc-Inferieure). It is easily re- 
cognized, even when crushed and distorted, by the sharply angular 
border of the umbilicus, as well as by its sculpture. 
8harpe flgured a specimen of the present species (now in the 
British Museum, J7o. 88640) under the name N. Reocomiensis, and 
one of the specimens figured by Mantell as W. elegans proves also 
to belong to N. Deslongcliampsianus. 
Horizon. Upper Neocomian. Upper Greensand. Lower Chalk. 
Localities. British. Warminster, Wiltshire ; Sandrock Spring, 
Isle of Wight (Upper Greensand) ; Yentnor, Isle of Wight (Chlo- 
ritic Marl) ; Niton, Isle of Wight (Lower Chalk) ; Cliffe Anstey, 
Devizes, Caine, Wiltshire ; Sussex ; Chard, Chardstock, Somerset- 
shire (Chalk Marl) ; Lewes, Sussex (Grey Chalk). — Foreign. South 
of France (Upper Neocomian). 
Well represented in the Collection, which contains the specimens 
figured by Sharpe and by Mantell. One of the specimens (C. 961) 
was presented by J. E. Lee, Esq., F.S.A., F.G.S. 
Nautilus pseudoelegans, d’Orbigny. 
1835. Nautilus glohosus, Potiez and Michaud {fde Gosselet, Etudes 
PaRontologiques sur le Departement du Nord — Extrait des Mem. 
Soc. Imp. des Sciences, de Agriculture et des Arts de Lille, pp. 5, 
1840. Nautilus pseudoelegans, d’Orbigny, Paleontologie Fran^aise (Ter- 
rains Cretaces), vol. i. p. 70, pi. viii., pi. ix. 
