NAUTILUS. 
122 
something larger at one end, but not margined: joints 
eight or nine, hardly distinguishable, separated by straight 
lines: aperture a little contracted, not oblique nor mar¬ 
gined, with a small syphon : length about the tenth of an 
inch. 
At Sandwich: very rare. 
18. Nautilus Radicula. Radicle Nautilus. 
Montagu , pi. 6. f. 4, and pi. 14. f. 6. 
Shell oval-oblong or somewhat conic, straight, tapering, 
smooth, brown, opake: joints varying from two to nine, 
globular and very deeply divided ; aperture sometimes ex¬ 
tended to a conical point, sometimes a mere small round 
opening at the top of the primary joint: the smaller end 
has also the joints compact and approximate, and some¬ 
times the terminal joint is conical and pointed : minute. 
In fine sand. r. m. 
19. Nautilus subarcuatus. Crooked Nautilus. 
Montagu y pi. 6. f. 5. 
Shell glossy-white, transparent, sometimes covered with 
a brown skin, tapering and slightly curved, with three di¬ 
stinct smooth globular joints, and numerous others which 
are hardly conspicuous : aperture a small produced sy¬ 
phon: the articulations or joints are sometimes to be num¬ 
bered to the amount of ten : minute. 
In fine sand: very rare. v. m* 
20. Nautilus costatus. Ribbed Nautilus. 
Montagu , pi. 14. f. 5. 
Shell nearly cylindrical and straight, a little tapering to 
an obtuse point, brown: joints twelve, sometimes only six, 
raised and well defined, furnished with four equidistant 
strong ribs running the whole length of the shell: aperture 
ending in a short conic syphon: length above the eighth of 
an inch. 
T r ariety A. Quite cylindrical, with five joints and seven 
ribs, truncate at one end, the other terminating in a slen¬ 
der cylindrical process as long as its annexed joint. Mon¬ 
tagu, pi. 19. f. 2. 
Variety B. Quite cylindrical, with five joints and four 
ribs, 
