54 salpidj:. 



very extensive and interesting tribe of Mollusca, one so 

 little examined, that the identification of well-known 

 species with the figures and descriptions of O. F. Miiller, 

 and other authors quoted, is disputed by some of our ablest 

 naturalists. The whole subject has to be re-investigated : 

 the brief notices and slight figures given by the older natu- 

 ralists are insufficient for accurate determination. Several 

 years must elapse before the task can be undertaken with 

 success. In the mean time this outline may be ser- 

 viceable. 



