NAUTILUS. 123 



ribs, and the extremities like the last variety. Monfagu, 

 Suppl. p. 84. 



In fine sand. v. m. 



21. Nautilus jugosus. Jointed Nautilus. 

 Montagu, pi. 14. f. 4. 



Shell opake, brown, tapering, nearly cylindrical, very 

 slightly curved, with nine somewhat globular joints mark- 

 ed with numerous longitudinal ribs ; the terminal joint of 

 the smaller end produced and longer than those which are 

 near it : aperture produced to a conic syphon : length the 

 eighth of an inch. 



In tine sand. v. m. 



22. Nautilus spinulosus. Prickly Nautilus. 

 Montagu, pi. 19. f. 5. 



Shell pale chesmit, with three very globular joints, co- 

 vered with spines which all incline to the posterior end ; 

 the upper bulb a little elongated to form a syphon : length 

 the tenth of an inch. 



Variety. Slightly curved and taper, with eight not so 

 much inflated joints, and covered with tubercles rather than 

 spines. Montagu, Suppl. p. 86. 



In fine sand. 



23. Nautilus bicarinatus. Double-ribbed Nautilus. 

 Montagu, SuppL p. 86. 



Shell somewhat cylindrical, curved, tapering a little to a 

 rounded point: joints eleven, rather globular, with two 

 slight longitudinal ribs, one along the arc, and another on 

 the opposite side ; the larger end terminating in a produ- 

 ced syphon : length the eighth of an inch. 



In fine sand. v. m. 



24. Nautilus linearis. Linear Nautilus. 



Montagu, pi. 30. f. 9. 



Shell glossy-white, transparent, smooth, a little flat- 

 tened, linear, quite straight, of nearly equal size through- 

 out or slightly tapering ; furnished with faint and rather ob- 

 lique ribs at the narrower end only, which disappear about 

 half way up : joints about fourteen, a little obliquely di- 

 M 2 vidcd, 



