MANGELIA. 481 



rouglienetl by strong and highly projecting rather distant 

 longitudinal ridges (of which there are eight or nine on 

 the body-whorl), and by revolving thread-like elevated 

 lines, that traverse alike the ridges and their broader con- 

 cave intervals. The ridges continue to the base of the 

 body, and extend, although in diminished volume, towards 

 the suture, from top to bottom of the principal coils. The 

 first of the spiral threads, of which there are usually four 

 more conspicuous ones on the principal turns of the spire 

 (the exact number seems to vary, there being, according to 

 Loven, from fifteen to seventeen upon the body, and six or 

 seven on the penult volution) runs immediately beneath 

 the fine and wavy sutural line ; they are minutely and 

 densely squamiferous, the scales being caused by the pas- 

 sage over the spiral threads of most densely disposed 

 microscopic lamellae, that run parallel to the perpendicular 

 ridges. Under a high magnifying power very many still 

 more minute revolving series of scales may be perceived 

 upon the body- whorl. The spire ends in a small but not 

 acute apex, and is about half as long again as the body ; 

 it is composed of seven volutions, that are of moderate 

 height, rather slow longitudinal increase, and somewhat 

 square-cut, being more or less angulated above, not much 

 rounded in the middle, and shelving in a little below. 

 The body is peculiarly small, and is not at all ventricose, 

 but almost immediately commences attenuating to a short 

 canal, that does not lean to either side. The mouth, 

 which in fully matured examples occupies but little more 

 than a third of the total length, is very narrow, especially 

 anteriorly ; the throat is quite smooth, and is occasionally 

 stained with a darker brown than the external tint. The 

 outer lip is sharp, simple, jagged at the edge by the spiral 

 threads of the exterior, scarcely projecting, little curved, 



VOL. III. 3 Q 



