NAUTILID^. 
347 
Aturia Parkinsoni, Edwards, sp. 
1811. Xautilite ivith sinuous diaphragms, Parkicson, Organic Remains 
of a Former World, vol. iii. p. 105, pi. vii. f. 15. 
1849. Nautilus Parkinsoni, Edwards, Mon. of the Eocene Mollusca, 
pt. i. Cephalopoda (Mon. Pal. Soc.), p. 49, pi. yii. 
1872. Nautilus Parkinsoni, Whitaker, Geology of the London Basin ; 
Mem. Geol. Sury. of England and Wales, yol. iy. pt. i. Appendix, 
p. 598. 
1877. Nautilus Parkinsoni, Whitaker, The Geology of the Eastern End 
of Essex ; 3Ieni. Geol. Sury. of England and Wales (48 S.E.), 
p. 26. 
? 1886. Nautilus Parkinsoni, Kaufmann, Beitriige zur geol. Karte der 
Sch\yeiz, Lief. xxiy. p. 301. 
1887. Aturia Parkinsoni, Geinitz, Leber Nautilus Alabamensis, Morton, 
Nautilus ziczac, Sowerby, iind Nautilus linyulatus, v. Buch ; Neues 
Jahrbuch fiir Min. &c. Band ii. p. 56, 
Sp. Char. Shell (cast) inflated, somewhat flattened on the sides 
and rather narrowly rounded on the periphery. Umbilicus closed. 
Septa approximate ; sutures strongly arched forwards ; lateral lobes 
broad, but ending in a narrow, bluntly pointed projection, which is 
separated from the broader portion by a slight constriction. Si- 
phuncle large, situated nearly exactly halfway between the centre 
of the septum and the periphery of the preceding whorl. Test 
smooth. Body- chamber unknown. 
liemarks. The specimen upon which the present species was 
founded consists of the casts of three yery large chambers, admirably 
figured by Edwards, the plate being engrayed by J. de Carle Sowerby, 
with his customary skill. In addition to the type specimen 
(No. 43869), the British Museum possesses another large one (from 
Colchester) (69571), which retains the test on one side, the other 
being much crushed. By removing part of the outer whorl on this 
side, the inner one has been exposed, and the siphuncle is thus laid 
bare in the younger part of the shell in two places. Here it is 
seen to be distinctly dorsal, the lower edge of its orifice almost 
touching the periphery of the preceding whorl. The siphuncle, as 
in the type specimen, appears to have been contained in a tubular 
sheath, which exhibits no tendency to expand into a funnel-like 
form betw^een the septa, as is usually the case in Aturia. The 
Colchester specimen also shows that the siphuncle in Aturia Par- 
kinsoni gradually shifted its position from the dorsal margin till it 
approached the centre of the septum ; but whether it ever reached 
the centre cannot at present be determined. At any rate the 
Colchester specimen shows it in three different positions. 
