TUERITELLA.— Plate III. 



ceding, save that the latter whorls arc more sharply 

 angled above and below. The ribs which impart this 

 angular structure to the whorls just before the growth of 

 the shell is matured, are much more strongly developed 

 in some specimens than in others ; they are nevertheless 

 shaqjly defined, and never have the obtuse swoUen ap- 

 pearance presented in the T. lentiijhwsn . The sutural 



grooving of the middle whorls is nearly obliterated, as in 

 that species, by their flattened and close contact. In 

 colouring, the T. goniostoma is characterized by a very 

 dense marbled or mottled pattern of grey-black, some- 

 times a little rusty ; and exhibits no indication of the short 

 transverse linear dashes which serve to distinguish the 

 T. letiliginosa. 



