XAUTILID.E. 
353 
lobes oblique, lanceolate, elongate, extending nearly to the dorsal 
mai:gin of the preceding whorl. Body- chamber deep, equalling | 
of the last whorl. Segments of the siphuncle very rapidly expand- 
ing. Test thin, covered with very fine striae, which are parallel 
with the edge of the aperture. Surface ornamented with semi- 
circular, transverse, approximate zones or bands of a reddish colour, 
beginning in the umbilical depression and extending to the edge of 
the periphery, upon which they break up into little patches which 
follow the direction of the striae. 
llemarlts. This species has been regarded by many authors as 
equivalent to J. Sowerby's Xautilus ziczac but a critical com- 
parison of the two species shows that they are really quite distinct, 
the present species having a much more compressed shell than 
Sowerby’s. Passing over the numerous references to Aturia Atari 
in the works of English and Continental authors, many of which 
are enumerated at the head of this description, we find the most 
recent account of that species in a paper by M. E. A. Benoist, entitled 
“ Coquilles Eossiles des Terrains Tertiaires Moyens du Sud-Ouest de 
la Erance ” h This author restricts the species under discussion to 
those forms which have been derived from the Miocene of South- 
western Erance and of Italy, and, taking the Dax form as typical, 
this disposition of the species seems to hold good. There are still, 
however, some forms from other countries recorded, and sometimes 
figured, whose afiPinities it is difficult to determine without an appeal 
to the actual specimens ; and even with that advantage a decision 
might be hazardous, owing to the fact that the specimens obtainable 
are often only fragmentary casts. In such a condition is that 
figured by Meneghini^ under the name Nautilus {Aturia) zigzag^ 
Sow., and therefore I have omitted it from the list of references to 
the present species, though, so far as Meneghini’s form can be made 
out from the figures, it may possibly belong to it. There is very 
great difficulty, however, in comparing these fragmentary casts with 
the Dax specimens, which are quite in the condition (save the loss 
of the animal matter in the shell) of recent shells. It may be men- 
tioned that there is a large fragment of an Aturia in the Collection 
(Xo. 73358) (a cast consisting of four chambers) that bears a 
very close resemblance to the large fragment figured by Meneghini 
{loc. cit.), which it exactly equals in size. Meneghini’s specimen is 
1 Actes de la Societe Linneenne de Bordeaux (Feb. 1889j, vol. xfii. ser, v. 
livr. i. p. 20, pi. ii. ff. I a, J b. 
^ Paleontologie de file de Sardaigne, 1857 (pt. iii. of the ‘ Voyage eu 
Sardaigne ’ of General La Marmora), p. 453, pi. H. ff. 2, 2'. 
PAET II. 2 A 
