UNIVALVES. 



PLATE XL. 



Genus. BULLA, 



Character. Shell spiral, spire not appearing, but folded up in a hollow centre, 

 at the top of the body ; beak none ; mouth wide, and spread out ; the general form 

 oval, or rounded ; columella plain. 



Species, 



No. 1. Bulla cinctoria. Shell oval, of an olive-green colour, banded with trans- 

 verse shades of brown and white, three in number on the body, and one at 

 the top ; inside of the mouth purple, with bands of gray and white. 



No. 2. Bulla ferruginosa. Shell of a pale pink colour, the inside of a white 

 and rust colour ; the body ornamented with party-coloured bands of white 

 and brown ; the spire wholly obliterated, as is usual in this genus. Native 

 place unknown. 



Genus. HARP A. 



Character. Shell spiral, ovate or swelling out, having compressed longitudinal 

 ribs, sharpened with an angle or point ; aperture below emarginated ; no canal ; 

 the columella smooth ; the base acute. 



Species. 

 No. 1. Harpa grandiformis. Shell richly mottled with brown, pink, and white 



streaks, placed in irregular waves ; the maxilla oris spotted red ; the mouth 



large and patulous. Found in almost all the islands of the West Indies. 

 No. 2. Harpa delicata. Shell very slender, and elegantly marked with red 



streaks ; the beak undulated with strongly marked ridges ; the mouth of a 



pale brown. 

 No. 3. Harpa urniformis. Shell of a pale purple, with transverse bands of red ; 



the top of the spire blue ; the general form much resembling an ancient 



sepulchral urn. 



REMARKS. 



The two genera above described have some resemblance to each other in their general cha- 

 racter, except that the Bulla is without any external spire, and also wants the opening at the 

 bottom of the shell. The Harpa is of an elegant and graceful form, and is distinguished 

 chiefly by the ribs which adorn the whole external part of the shell ; the spire is very short, 

 and crowned at the top with a small circular knob or capitulum, something in the manner 

 of the genus Pyrula. The maxilla oris, or cheek, is also divided from the body by a curious 

 haunch or slanting opening crowned with a knob, which gives the whole shell a striking cha- 

 racter peculiar to itself. 



The Bulla is not uncommon upon the English and French shores, but the Harpa is found 

 only in the Southern and Pacific Seas, and may be regarded as one of the most laboured of 

 Nature's works, as it presents to the eye many little circumstances of high finishing and 

 painting, which an artist can by no means easily imitate, or convey to the mind by any la- 

 boured description whatever. The Harpa was erroneously placed by former Authors with 

 the genus Buccinum, into which error Linnaeus also fell, from some mistake respecting its 

 general form. 



