TROCHUS. 521 



long ; ill general it occupies half the length of the shell, 

 and more than half of the hasal diameter ; it is pearly 

 within, and is not distinguished hy any sculpture. The 

 outer lip is acute, and generally bordered with rather a 

 wide strip of the external colouring, with a predominancy 

 of dirty green, which latter tint is more particularly ap- 

 parent at the base of the short and not particularly oblique 

 columella, which is white, subarcuated above, a little 

 reflected, and somewhat flattened behind. The size is 

 about that of the flattened variety of cinerarius. 



We have taken alive in the islet of Herm, near Guernsey, 

 a very remarkable variety which exhibits no trace of a per- 

 foration when adult, and only a slight indication of one 

 when young. Except that it is rather more elevated, and 

 that the painting of the smoother and rather more convex 

 base displays a more reticulated appearance than in the 

 majority of individuals of the commoner form, we can 

 discern no difference in the characteristics. 



The animal is of a general dusky greenish purple hue. 

 The snout is finely crenated at its edge and is of a greenish 

 colour, with transverse purple lines. The tentacula are long 

 and setaceous, minutely ciliated, and conspicuously ringed 

 with purple. Between them are two well-developed but 

 well- separated crenated head-lobes. The eye-peduncles are 

 stout and greenish- white, with greenish-purple eyes. The 

 neck-lappets are pale, marked with greenish opaque yellow 

 dots and purple : the inner one has a fringed margin, the 

 outer is even-edged. The lateral cirrhi, which, though 

 long, are not so long as in cinerarius^ are finely rayed 

 with purple, and have each a white tubercle and minute 

 mucronated process at the base : there are three on each 

 side. The sides of the foot are closely lineated with 

 greenish brown or rich purple ; the lateral membranes 



VOL. II. 3 X 



