389 



others, must also be referred to this group. The lengthy triserial 

 ribbon of Cyrtulus, or Tritonidea, for example, exhibits no true or 

 immediate affinity with the comparatively short and septiserial dental 

 armature of Triton or Ranella. Thus the author is induced to 

 dissent from Mr. Gray's view that Tritonidea is allied to Triton, but 

 agrees with him that the Buccinidce, forming an equally characteristic 

 natural family, are very close at hand. 



The lingual dentition, and in fact the whole anatomy of Terebra, 

 most unequivocally refer it to the Conidce, and not to the Buccinidte, 

 amongst which it is at present received. 



The author has not been able to detect lingual cartilages of the 

 usual character in Conus, Conorbis, or Terebra, but the walls of the 

 tongue-sac are stout, tough, and distinctly cartilaginous in structure; 

 indeed the whole organ, including its armature, very much resembles 

 the dental cheek-pouches of some Pteropods. 



The lingual ribbon of Pleurotoma is exceedingly minute, and the 

 parietes of the sac are not of that dense and unyielding character 

 which they exhibit in Conus, Conorbis*, and Terebra. Moreover, 

 in Pleurotoma the little lingual membrane is supported by two 

 rounded masses of cartilage composed of large spheroidal cells. The 

 rachis appears to be absent altogether, and tli re is but a single row 

 of elongated, slightly curved, and sharp-pointed teeth (differing con- 

 siderably from those of Conus and Terebra) in the pleurae. 



The tongue-strap of Mitra, although remarkably short, is triserial 

 like that of Murex, Purpura, &c. ; but the author has invariably 

 found that in those Mitres in which the sculpturing of the shell was 

 transverse, the pleural teeth were simple, uncinate, and mobile, while 

 in those species characterized by a smooth surface or longitudinal 

 sculpturing, the dental processes were small, straight, and numerous, 

 arising just within the posterior border of broad basal plates. This 

 difference is exactly such as exists between the lingual dentition of 

 the respective groups to which Murex and Tritonidea belong. 



Harpa and Oliva are very closely allied, by the general configu- 

 ration of the body and the characters of the lingual dentition, though 

 it must be remembered that the tongue-strap in the former is so very 



* Several specimens of a recent species of this genus (hitherto known only in a 

 fossil state) were obtained from depths ranging between 10 and 20 fathoms, 

 within the barrier reefs surrounding the Feejee Islands. 



