102 Proceedings of the Royal Society of Victoria. 



Mangilia flaccid a, sp. nov. 



Shell narrowly elongate, with a rather acute apex in unworn 

 specimens, but most of the adult specimens hitherto examined 

 appear blunt and obtuse on account of apical erosion. 



Embryonic whorls about two, smooth and shining, and slightly 

 convex ; the succeeding whorls number about four or five, and 

 are strongly costate. 



Spire whorls are subangulate a little below the suture, giving 

 t he latter the appearance of being soniewhat impressed. Each 

 whorl bears from ten to twelve strong costse, usually the former 

 number; the costse are slightly oblique, are usually narrower than 

 the interspaces between them and extend of a uniform breadth 

 from the anterior suture to the posterior angulation, thence 

 to the posterior suture tapering slightly, and forwardly directed 

 to a slight extent. On the anterior lower half of the body-whorl 

 the costse are backwardly arched, and thin out towards the 

 columella. The costfe and interspaces are both crossed 

 transversely by fairly strong and intermediate fine series of 

 spiral threads, the strong and prominent threads numbering 

 from three to six to a whorl, with several tine threadlets between 

 them. 



In young, and in well preserved adult shells, the coarser spiral 

 threads where they cross the costae, cause the latter to have a 

 regular beaded or granulated appearance, but in some adult 

 specimens there appears to be a tendency for this tpye of 

 ornament to become indistinct or obsolete towards the body- 

 whorl. Parallel to the costfe fine strife-like lines of growth are 

 discernible under a lens. Aperture ovate, with a somewhat 

 narrow but well defined sinus posteriorly just below the suture, 

 and witli a short broad and shallow anterior canal. 



Columella smooth and slightly twisted. The outer lip in adult 

 specimens has a thin edge from the sinus to the anterior lower 

 margin of canal, with a well-marked varicose thickening behind, 

 extending from the anterior canal up to and then round the 

 sinus to the suture, where it thins out in a pad-like form on the 

 inner lip. Outer lip somewhat eff'use anteriorly. 



Colour white to ci'earay, with a pale or faded violet-brown 

 broad band on the anterior slope of the body-whorl, and a faint 



