162 Description of Neiu Species and Varieties of Shells, 



them species. It is difficult to avoid the conclusion that the 

 whole group is more comprehensive than a species, while the 

 several local types are of less than specific value, and that it 

 is impracticable to recognise in these shells types of the ave- 

 rage value of species. 



In attempting to classify such of the varieties as are now 

 before us, we have been surprised at the great constancy of 

 coloring in respect of the kinds and distribution of color. The 

 differences of color in a given variety are almost wholly in 

 their greater or less depth. 



The following varieties are in the collection of Mr. Chitty, 

 to whom I am greatly indebted for information respecting 

 them. There are a few more in the collection at Amherst 

 College. 



a. Dark colored varieties. In this group, the dark colors 

 fade to a pale brown or cinnamon color. 



Yar. NiGRESCENS. Shell robust in the lower part, conic 

 above : black on the last whorl and on several of the upper 

 whorls, fading into brown in the middle, with a dingy white 

 stripe anteriorly and a red lip : with a few strise behind the 

 lip. In some localities the shell is of medium size and form, 

 rather more coarsely striate on the last half of the last whorl, 

 and faintly striated on the first half. Inhabits Portland, and 

 Manchioneal in St. Thomas-in-the-East. 



Var. soLiDA. Shell very thick and robust : very dark or 

 blackish brown at both extremities, pale brown along the mid- 

 dle, with a pure white widening stripe next below the suture 

 of the last whorl ; pink in the lip and behind it : very coarsely 

 striated on the last whorl, otherwise feebly striated. In paler 

 specimens a faint tinge of red is seen on both extremities, and 

 the lip is white. Inhabits the vicinity of Peace R. in the east 

 part of Manchester, 



Var. LEVIS. Shell robust but rather thin : livid black in 

 the upper whorls, pale livid brown along the middle, anteriorly 



