NAUTILUS. 
117 
NAUTILUS. 
Shell with a single valve, consisting of compart¬ 
ments or cells, communicating with each other by 
means of a small perforation or tube. 
A. With the spires detached. 1. 
B. With the spires connected. 2 to 12. 
C. Elongated, and more or less straight. 13 to 24. 
*1, Nautilus Spirula. Crosier Nautilus. Fig. 77. 
Lister , pi. 550. f. 2. 
Shell spiral, extremely thin and brittle, transparent, 
white or cream-color: spires five, cylindrical, detached 
from each other, divided into numerous chambers at nearly 
Equal distances, which are distinguished by a depressed 
circular line on the outside ; the primary volution running 
nearly straight and very remote from the uext ; the re¬ 
naming ones growing gradually less and io'ely involuted 
kt not touching each other; the line or junction also be¬ 
comes gradually deeper towards tin smaller end, giving the 
different divisions a more rounded appearance, till the ter¬ 
minal ones appear somewhat globular: aperture orbicular, 
pcrlaccous within, the chambers separated by thin pearly 
plates, with a small tube of communication which is placed 
nearoue side : diameter nearly an inch ; of the larger volu¬ 
tion nearly a quarter of an inch. 
Two specimens of this interesting addition to our native 
stock, wer on the strand between Kenmare harbour 
and Ball ay, in the county of Kerry, Ireland, by 
our inteil ,: : mu. h respected friend, Mr. O’Kelly of 
Dublin, in i. . erof 1817; where, as he observes, the 
waves of iiie Atlantic come unbroken from the shores of 
America; and where he also found at the same time, the 
Helix ianttiina with the animal in it, and the rare Lenas 
sulcata, v. tn. 
B. With the sjjires connected . 2 to 12. 
2. Nautilus lacustris. Fresh-icater Nautilus. 
Montagu , pi. 6. f. 3— Walker, f. 28. 
Shell horn-color or rufous-brown, smooth, glossy, trans¬ 
parent, 
