PLATE XXII. 
1, 2, 3. Scaphites Striatus. (Striated Scaphite.) Inner volutions umbilicate, wholly concealed 
by outer one; ambit tumid; aperture entire, ovate, marginate; margin prominent; surface, with 
many oblique, annular, bifurcate striae; septa concave. Situation of siphunculus unknown. Length, 
1 in.; thickness, \ in.; width, in. 
4, 5. S. Costatus. ( Bibbed Scapliite.) Volutions convex, laterally compressed; inner volutions 
wholly inserted, concealed; sides with many, transverse, furcate striae; sides of outer volutions 
smooth, with eight or ten oblique, nodular projections; ambit broad, convex. Length, 1 in.; width, 
•§- in.; thickness of ambit, \ in. 
6, 14. S. Tubereulatus. (Tuberculated Scaphite.) Involute, umbilicate; inner volutions con¬ 
cealed ; with series of wide-set ribs from inner margin; ambit rounded. Length, 1 in. 
7, 8, 9, 15. S. Equalis. (Equal Scaphite.) Involute, umbilicate; inner volutions concealed; 
inner parts of sides with projecting, distant ribs; ambit enlarged, ventricose, thickened; aperture 
incurved; outer coating pearlaceous. Length, 1 in. 
10, 11, 12, 13. S. Obliquus. (Oblique Scaphite.) Obliquely involute; umbilicate; inner volu¬ 
tions concealed; sides transversely striate; striae bifurcate or trifurcate; ambit rounded. Length, 
1 in.; width, f in.; thickness, 1 in. 
16. Nautilus Tetragonis. (Quadrangular Nautilus.) Discoidal, flattened, with tetragonal 
volutions; ambit slightly concave, with small spiral ridge within angles; sides crossed by sharp bent 
striae, rising into ridges on edges; septa outwardly concave. 
17. N. Inequalis. (Unequal Nautilus.) Spheroidal, umbilicate; aperture nearly round; trilo¬ 
bate, embracing volutions, and nearly equal to half diameter of shell in length and width; septa 
curved, remote in inner volutions, contiguous in outer ones; siphunculus situate near inner margin 
of septum. 
18. N. Multicarinatus. (Many-lceeled Nautilus.) Discoidal, sub-globose, umbilicate; umbilicus 
large, deep, angular; sides of inner volution half-exposed; ambit compressed, very broad, flattened 
with centre plain, and with four sharp carinse on each side, exclusive of the one investing margins 
of umbilicus. 
19. N. Cariniferus. (Keeled Nautilus.) Discoidal, sub-globose, umbilicate; inner volutions 
half-exposed within very large, deep, sharp, margined umbilicus; ambit very broad, with centre plain, 
flat, and with two Carinas on each side and rounded broader one outside these; lip, with deep sinus. 
20. N. Cyclostomus. (Circle Nautilus.) Partly spiral; inner volutions exposed, outer ones 
rapidly increasing to a nearly straight line; sides crossed by fine, flexuous striae; suture outwardly 
concave; aperture circular; siphunculus situate near outer edge; number of volutions variable. 
21. N. Pentagonus. (Pentagonal Nmtilus.) Discoidal witli five volutions; inner ones about 
one-tliird concealed; ambit sub-carinated; aperture orbicular, obscurely five-angled indented by 
preceding volution; sides flattened, with a few oblique wrinkles; septa numerous, slightly concave; 
siphunculus central. Greatest diameter 8i in. 
22. N. SinuatUS. (Sinuous Nautilus.) Very thick, umbilicate; inner volutions few, wholly 
concealed; sides depressed, conical, with close, fine, elevated, concentric strife; ambit convex; aperture 
obtusely sagittate, truncated; septum elevated towards front, with large marginal sinus on each side; 
umbilicus shallow; siphunculus one-third length of aperture from ambit. Greatest diameter 5 in.; 
thickness 2\ in. 
( 26 ) 
