132 FUSID^. 



produced ; canal exserted ; columella obscurely plicate. Oper- 

 culum irregularly ovate ; apex obtuse ; nucleus inconspicuous. 

 The dentition of this mollusk appears to relate it somewhat 

 to Ptychatractus, and I prefer to place it in the same subfamily 

 with that shell, rather than make a new family for it. Norman 

 shows that Meyeria is preoccupied by M'Coy for a genus of 

 fossil crustaceans, and he therefore proposes the generic name 

 Metzgeria ; but I see no advantage (and much disadvantage) in 

 changing names because they happen to have been previously 

 used in some other department of zoology. 



Subfamily PERISTERIINjE. 



Peristernia, Morch. 



Distr. — 30 sp. Polynesia, Philippines, Australia, Indian 

 Ocean, Zanzibar, Mauritius. P. nassatula, Lam. (xlviii, 93). 

 P. incarnata^'Desh., var. (xlviii, 94). P. Belcheri,'Rye. ( xlviii, 96). 



Shell turreted, not umbilicated; whorls longitudinally ribbed ; 

 aperture oval ; canal moderate and recurved ; outer lip thin and 

 crenulated ; columella with one or two slight plaits anteriorly. 

 The want of umbilicus, less distinct columella folds and recurved 

 canal are the principal (and not sufficient) distinction from 

 Latirus. ' 



Latirus, Montfort. 



Syn. — Chascax, Watson. Polygona, Schum., 1817. Plicatella, 

 Swains. 



Distr. — 34 sp. Polynesia, Philippines, Australia, Indian Ocean, 

 Panama, W. Indies, Madeira. L. infundibulum, Gmel. (xlviii, 95). 



Shell turreted, fusiform, sometimes umbilicated ; spire pro- 

 duced ; whorls nodulous, aperture oval-oblong ; outer lip thin, 

 crenulated ; columella straight, with two or three small oblique 

 plaits in front. Mr. H. Crosse remarks upon the insufficiency of 

 the diagnosis of Latirus by Montfort and H. and A. Adams, and 

 proposes to relegate the species to Turbinella ; that genus, how- 

 ever, may be more advantageously restricted to the forms for 

 which the genera Vasum and Mazza have been constituted. 



Swainson's group Plicatella has been adopted by Messrs. 

 Adams as a subgenus of Latirus, having " spire moderate, 

 whorls angular, concavely depressed around the upper part," 

 but these are only comparative characters, and I prefer to sup- 

 press the group rather than place in it species having no relation 

 thereto, as Messrs. Adams have done. The umbilicus shows 

 more distinctly in most of the species of Latirus than in those 

 of Peristernia, but in some of them it is not any better marked ; 

 Latirus, however, differs in form from Peristernia, the species 

 having longer spire and canal, the columella generally straight, 



