tS6 MOLLUSCA. CEPHALOPODA. Orthoceiia. 
number, the first the longest, the last produced into a conical neck, with a 
round aperture. The colour brown. 
29. O. costata. — Subcylindric, straight, with four longitudinal 
ridges. 
N. cos. Mont, Test. Brit. 199, t. xiv. f. 5. — On the Kentish coast, Mr 
Boys. 
Length ;|th of an inch ; tapering little ; chambers subglobose, twelve in 
number ; the ribs strong ; the neck of the last chamber shorter than in the 
preceding species. A variety is recorded by Mont. ib. Supp. 84, t. xix, f. 2, 
as having only five joints and seven ribs, anteally truncate; retrally termi- 
nating in a |solid produced process. A second variety is likewise noticed at 
the same page, in Avhich the joints are five in number. 
30. O. hicarlnata. — Subcylindric, arcuated, the joints bicari- 
nated. 
N. bicar. Mont, Test. Brit. Supp. p. 86. — Sandwich, Mr Boys. 
Length |th of an inch ; joints eleven, globose, the ribs on the convex and 
concave sides ; anteally the mouth is produced ; retrally there is a rounded 
point. 
31. O. linearis. — Straight, compressed, the retral half with 
faint oblique ribs. 
N. lin. Mont, Test. Brit. Supp. 87, t. xxx. f, 9. — Dunbar, Capt. Laskey. 
Length |th of an inch, nearly linear ; the chambers are about fourteen in 
number, the septa oblique ; the anterior end smooth, terminating in a pro- 
duced mouth, the other rounded. 
With spines or tuhercles. 
3^. O. spinulosa. — Spines numerous, reflected. 
N. spin. Mont. Test. Brit. Supp. 86, t. xix. f. 5. — Sandwich, Mr Boys. 
Joints three, globose, the last produced to form the mouth. Montagu no- 
tices a variety with eight subglobose joints which are tuberculated, which he 
found in the Boysian cabinet. Its length ^^th of an inch. 
Chambers smooth. 
33. O. recta. — Shell nearly straight, joints transverse, cham- 
bers subcylindric. 
N. rectus, Mont. Test. Brit. 197, t. xix. f. 4. 7 — Sandwich, Mr Boys. 
Form a little tapering, length about y^th of an inch, with eight or nine 
chambers. 
.34. O. radiciila.-^^heM straight, joints transverse, chambers 
subglobose. 
N. rad. Mont. Test. Brit. 197, t. vi. f. 4, and t. xiv. f. 6. — Sandwich. 
“ This species appears to be subject to very considerable variation with 
respect to the extreme joint at each end, as well as in the number. In some 
the aperture is extended to a conic point ; in others it is only a small round 
opening on the extreme articulation, which is globose ; the smaller end, in 
some, is rounded ; in others conic, pointed.” 
35. O. subarcuata.^^hfM. subcylindric, subarcuated, with 
