
ss CLASS BPRS T. 
UNIVALVE TESTACEOUS MOLLUSCA. 
ORDER ICEPHALOPODA. 
Head of the animal emanating from a bag-shaped mantle, and 
surrounded by inarticulated arms, provided with a sucker, and in- 
vesting the month; two sessile eyes; mouth furnished with two 
horny mandibles ; three hearts ; the sexes in separate individuals. 
Famity I.—NavTILacEA. 
Shell discoid, with a central spire, the cells short, and not ex- 
tending from the centre to the circumference. 
Genus 1.—NavtTitus.—Linneus. 
Shell discoid, spiral, multilocular, with simple partitions; volu- 
tions contiguous, the last or body-one enveloping the rest; the 
septa transverse, and externally concave, perforated in the disc; 
margins entire. 
1. N. Becarii, pl. I, f. 11.—First Edition, pl. 52, f. 11; Montagu’s Testacea 
Britannica, p. 186, pl. 18, f. 4; Walker’s Minute Shells, f. 63. 
Shell with four or five volutions, the joints deeply sulcated; ten septa in the first 
whorl ; convex above, and flat beneath, the markings less distinct, aperture turned 
downwards, and not clasping the body volution ; siphon small, and usually situate in 
the convex front; covered with a brown epidermis, but white when divested of its 
skin; in which condition, if the animal is alive, it is of a crimson colour, size not a 
line. Found on the Devonshire coast, and in the Frith of Forth, adhering to the 
Fucus vesiculosus, the roots of Algw, and on Oyster shells. 
2. N. Becarii perversus, pl. I, f. 12.—First Edition, pl. 52, f. 12; Montagu, p. 
187, pl. 18, f. 6; Walker, f. 64. 
Shell with the volutions reversed, and agreeing in every respect with the descrip- 
tion of Nautilus Becarii. 
plentiful as Becarii. 
3. N. crassulus, pl. 1, f. 5.—First Edition, pl. 51, f. 5; Montagu, p. 191, pl. 
18, f. 2; Walker, f. 70. 
Shell strong, spiral, with numerous close-set elevated septa; sides compressed, 
similar, doubly umbilicated, within which, part of the interior volution is seen ; aperture 
placed a little oblique, scarcely elasping the body, and provided with a siphon; colour 
cream white, sometimes brownish; size not more than half a line. Found at Re- 
culver ; very rare. 
4. N. umbilicatulus, pl. I, f. 8.—First Edition, pl. 52, f. 8; Montagu, p. 191, 
pl. 18, f. 1; Walker, f. 69. 
Shell spiral, compressed, umbilicated on both sides, subpellueid, with nine or ten 
raised septa; aperture clasping the body volution almost equally on both sides, the 
interior volutions being hid. The most minute of all the Nautili, about the fourth of 
It cannot be considered as a Zusus, because it is nearly as 
a line in size. 
5. N. depressulus, pl. I, f. 3.—First Edition, pl. 52, f. 3; Montagu, p. 190, 
pl. 18, f. 9; Walker, f. 68. 
Shell spiral, with about nine visible septa, radiating from the centre in curved 
lines, distinguished by their opacity, but not embossed; sides similar; in the centre 
is a small pellucid spot, which may be mistaken for an umbilicus; the aperture does 
not clasp the body so much as that of the N. calcar, from which it also differs in 
being much more compressed, having no carina, and in the concamerations being 
more numerous, and being only about half the size. 
6. N. inflatus, pl. I, f. 4.—First Edition, pl. 52, f. 4; Montagu, sup. p. 81, pl. 
18, f. 3. 
Shell spiral, with three lobed volutions; the first provided with five extremely 
ventricose articulations; anterior end subglobose; siphon situated as in N. Becarii. 
It is smaller, and less depressed than that shell, having only about half the number 
of articulations, whieh are much more tumid; colour opaque brown. 
sand on the Devonshire coast; rare. 
7. N. levigatulus, pl. I, f. 9, 10.—First Edition, pl. 52, f. 9, 10; Montagu, 
p- 188, pl. 18, f. 7, 8; Walker, f. 67. 
Shell spiral, with ten smooth, pale ferruginous brown, flexous rays marking the 
septa, which are rather deeper in colour, a little raised and radiating from the centre; 
both sides are equally and considerably convex, declining towards the edge, which is 
rounded but not strictly carinated ; aperture surrounded by a rim forming a triangle, 
so that the body is not intersected by the anterior end, but the volution is lost just 
below the margin of the first septum; thus differing from the N. calcar, whose 
hody is much clasped by the margin of the anterior septum. Found at Sandwich 
_and Seasalter; rare. 
8. N. calcar, pl. I, f. 1, 2.—First Edition, plap2, of. 1,2 Montagu, p. 189, 
pi. 15, f. 4; N. rotatus, Linnewau Transactions, VITI. p-. 114. 
Found among 
Shell smooth, spiral, body volution with six articulations, defined by flexous ele~ 
vated striw, radiating from the centre, but do not quite reach the margin, which is 
provided with a strong carina; both sides of the shell equally convex, smooth, and 
more elevated in the centre: interior volutions invisible after entering the aperture, 
which is semi-cordate in shape, clasping the body equally on both sides, and provided 
with a small perforation; colour brown. Found on the Devonshire coast, but very 
rare. 
9. N. crispus, pl. I, f. 6.—First Edition, pl. 52, f. 6; Montagu, p. 187, pl. 18, 
f. 5; Walker, f. 65. 
Shell with lateral volutions, having about twenty flexous, crenulated articulations in 
the exterior volution, defined by elevated strie; back carinated; interior volutions 
hidden; aperture semicordate, equal, lateral, clasping the body, and provided with a 
small siphon; glossy and pure white. Found at Sandwich, Sheppy Island, Teign- 
mouth, and Saleomb, Devonshire; and at Weymouth and Swanage, Dorsetshire; 
also the south coast of Wales. 
10. N. carinatulus, pl. I, f. 7.—First Edition, pl. 52, f. 1; Montagu, p. 195; 
Walker, f. 72. 
** An oblong carinated shell, with a narrow oval aperture; colour whiteish, trans- 
parent like glass. From Seasalter and Sandwich; very rare.” We have copied 
this, imperfectly figured and described, Shell from Walker. From the figure we 
should say that it belonged to the family Spherulacea of Lamarck. 
Famiy IJ.—Litvoacea. 
Shell somewhat spiral, the last volution continuous in a straight 
line. 
Genus 2.—Sprroitina.—Lamarch. 
Shell multilocular, partly spiral, and discoid; volutions contiguous, 
the last terminating in a straight line; septa straight, perforated by 
a tube. 
Subdivision I.— Convoluted. 
1, S. subarcuatula, pl. I, f. 27.—First Edition, pl. 52, f. 27; Nautilus subar- 
cuatulus ; Montagu, sup. p. 80, pl. 19, f. 1; Walker, f. 73. 
Shell subareuated, subconvoluted, the straight part containing about five cells; the 
posterior half convoluted; twelve visible concamerations, and very distinct; septa 
somewhat elevated; back carinated, and slightly indented at the division of the cells; 
anterior septa oblique, producing at the aperture a considerable slope from the back 
interiorly ; front margin not carinated, but obtusely rounded; siphon, placed near 
the back. 
2. S. similitua, pl. I, f. 22.—First Edition, pl. 52, f. 22; Nautilus similituus ; 
Montagu, p. 196, pl. 19, f. 3. 
Shell elongated, subarcuated, with elevated articulations ; the septa provided with 
small elevated tubercles, a row of larger ones in the centre of the back; apex incur- 
vated; aperture with a small produced siphon; colour opaque brown. Found at 
Sandwich and Sheppy Islands; rare. 
Subdivision II.—Shells nearly straight. 
3. S. Legumen, pl. I, f. 22, 23.—Orthocera Legumen.—First Ejition, pl. 52, 
f. 22, 23; Nautilus Legumen ; Montagu, sup. p. 82, pl. 19, f. 6, and A. Walker, 
f. 74. 
Shell subareuated, smooth, glossy, pellucid, white; slightly compressed, and a 
little tapering; the extremities rounded and somewhat contracted; anterior end 
surrounded by an oblique ridge, above which is an excerted siphon; with a consider- 
able aperture near to the concave side; septacight or nine in number, oblique, and 
visible through the shell; cells gradually decreasing in size towards the posterior end. 
Fig. 23 represents the aperture with the siphon. Length about an eighth of an 
inch; breadth about a sixth its length. Found in sand on the coasts of Kent and 
South Devon; very rare. 
Famity [I].—CrrtuoceraTa. 
Shell straight or nearly so, without any spiral volutions. 
Genus 3.—Noposarta.—Lamarck. 
Shell elongated, erect, or smooth, and slightly arcuated, sub- 
conic, nodose, consisting of a series of spherical volutions; the 
transverse septa perforated. 
1. N. subarcuata, pl. I, f. 18.—Orthocera subarcuata.—First Edition; Naz- 
tilus subarcuatus ; Montagu, 198, pl. 6, f. 5. 
Shell subcylindrical, subarcuated, with three distinct globose articulations at the 
superior end; the remaining divisions imperfectly defined, and abruptly tapering to 
