NAUTILUS. 



Plate III. 



Species 2. (Mus. Cuming.) 



Nautilus scrobiculatus. Naut. testa suborbiculari, 

 Itsvi, ad latera concentrice plicato-corrugatd, peram- 

 pliter spiraliter umbilicatd, aliidd, postice transversim 

 ferrugineo strigald, strigis latiusculis, subremotis. 



The excavated Nautilus. Shell nearly orbicular, 

 smooth, concentrically plicately wrinkled at the sides, 

 very largely spirally umbilicated, whitish, posteriorly 

 transversely streaked with rust, streaks rather broad 

 and somewhat distant. 



Solander, MS. Portland Cat. n. 3653. Dillwyn, Cat. 

 vol. i. p. 339. 



Nautilus crassns umbilicatus, Chemnitz. 



Hull. New Ireland. 



It has been shown by Dr. Gould, of Boston, United 

 States (Pro. Zool. Soc. 1857, p. 20), that under the old 

 name, N. umbilicatus, two species have been confounded. 

 " In looking over the shells of a dealer in Boston, 

 U. S. A.," says that accomplished naturalist, " I ob- 

 served three specimens of an umbilicated Nautilus which 

 struck me as differing essentially from the shell commonly 

 known as N. umbilicatus. A more careful examination 

 satisfied me that they were quite distinct; and I made 

 out a comparative description of them, intending to de- 

 signate the newly-observed one by the name texturatus, 



on account of its finely reticulated surface. But on re- 

 ferring to the several figures of N. umbilicatus, I found 

 that the figure of Lister, which represents the shell origi- 

 nally named umbilicatus, presented all the characteristics 

 of the reticulated shell, while all other figures represented 

 the smooth shining shell ordinarily bearing that name. 

 Prom both the descriptions and figures of authors I am 

 led to believe that the shell originally observed by Lister 

 has not been recognized by conchologists since his day. 

 Every writer except Pavanne expressly speaks of his shell 

 as smooth {Icevis, glatte), and his figure clearly refers to 

 the common shell. On the supposition, then, that these 

 are two distinct species, it is proper to restrict the term 

 applied by Lister to the shell represented by him, and to 

 substitute another for the shell ordinarily named umbili- 

 catus. The term scrobiculatus, indicated in manuscript 

 by Solander, and adopted by Dillwyn, and which has been 

 placed by others as a synonym, may be appropriately re- 

 stored to this species." 



The well-known N. scrobiculatus differs from the rarer 

 N. umbilicatus, the figure of which, in the next Plate, is 

 drawn from one of Dr. Gould's Boston dealer's specimens, 

 chiefly in being smooth, in being more or less plicately 

 wrinkled concentrically, and in having the painted streaks 

 larger, more distant, and of a paler rust-colour. 



June, 1861. 



