NAUTILUS. 349 



treme joint at each end as well as in the number : in some 

 specimens the aperture is extended to a conical point; in 

 others it is only a small round opening on the extreme arti- 

 culation which is globose ; the smaller end is also sometimes 

 crowded, and sometimes conical and pointed. 



spinulosus. 28. Shell straight, ovate-oblong, with 

 swollen spinous joints. 



Nautilus spinulosus. Montagu Supp. p. 86. t. 19- f. 5. 

 Inhabits the sea. Montagu. 

 Shell minute, and differs from N. Radicula only in being of a 



chestnut colour, and in having the joints spinous, so that Mr. 



Montagu suspects it may be one of the numerous varieties of 



that species. 



sub-arcuatus. 29. Shell sub-arcuated, rather cy- 

 lindrical, with three globose joints at the 

 larger end, and the remainder indistinct. 



Nautilus subarcuatus. Montagu Test. p. 198. t. 6. f. 5. 



Maton and Racket, in Lin. Trans, viii. p. 1 19. 

 Ledermuller Micros, t. 4. f. S. 



Inhabits the coast near Sandwich, very rare. Mr. Boys. 



Shell minute, about one tenth of an inch long; white, pellucid, 

 glabrous, sometimes covered with a brown epidermis ; aper- 

 ture a small produced syphon. 



bicarinatus. 30. Shell arcuated, with two oppo- 

 site longitudinal keels ; joints globose. 



Nautilus bicarinatus. Montagu Supp. p. 86. 



Inhabits the coast about Sandwich. Mr. Boys. 



Shell minute, similar in shape to the foregoing species, but is 

 more curved, and Mr. Montagu says it may be at once dis- 

 tinguished by a slight longitudinal keel along the arc, and 

 another on the opposite side. 



fascia. 31. Shell straight, with striated joints, 

 smooth and elevated at the partitions. 



Nautilus Fascia. Linnaus Syst. Nat. p. 1164. Schroeter 

 Eint. i. p. 17. Gmelin, p. 3373. 



Gualter, t. J 9. f. O. Martini, i. Vign. 1 . at p. 1 . f. D and d. 

 Inhabits the Adriatic. Linnaus. 

 Shell minute, conical, white ; joints closely striated longitudi- 



