50 



whorl with 4 or 5 raised striae, and by about four ones provided with two distinct keels, of 

 which one, at a little distance from the suture, the other at the periphery, accompanied on the 

 last whorl by a third keel, at a little distance from the periphery, nearly on the base; these 

 three keels are in typical specimens adorned by sharp nodules, about 30 on the upper keel, 38 

 on the peripheral one, and 34 on the visible part of the lower one; moreover there are 2 raised 

 spiral striae between suture and upper keel, 5 between this and the peripheral one and 2 in 

 the space between periphery and lower keel. This concerns the last whorl; on the upper ones, 

 the finer sculpture disappears gradually. Umbilicus bordered by a row of coarse, compressed 

 beads, 17 in number; space between basal and umbilical keel with 5 smooth lirae. The lower 

 whorls have a distinct, nearly horizontal space, from the suture towards the upper keel, with small, 

 radiating plicae, corresponding to the nodules, the spaces above and below the peripheral keel 

 are slightly concave, the suture laying by this construction in a sort of canal. Base nearly 

 flat, but slightly convex. Umbilicus funnel-shaped, rather large, pervious, its wall with raised, 

 concentric and radiating striae, more or less beaded; aperture rounded-quadrangular, with angles 

 at the ends of the keels, especially of the umbilical one; margin sharp, columella curved and 

 slightly reflected at the upper part; interior of aperture smooth, nacreous. 



Operculum many-whorled, outer 2 whorls broad; whorls sculptured by radiating and concentric 

 striae, causing a latticed appearance, radiating striae stronger on the distal half of each whorl. 



Alt. 4^^, diam. maj. 5Y5, apert. alt. 2, lat. 2Y0; diam. of umbilicus 2^2 Mill. 



This description is made from a specimen, which I consider as the type, as it shows the 

 characters in their full development. As however the name indicates, there are many varieties 

 or mutations. The variations of colour consist of the greater or lesser development of the rosy 

 colour, which is either limited to the last whorl or extends on the penultimate, even still on 

 preceding whorls, this colour is plain, or with a tendency to form flammules, a more important 

 difference consists in the more or less complete disappearance of the nodules on the lower keels, 

 which seems to coincide with the sharper sculpture of the interior of the umbilicus. I have 

 separated such specimens as : 



var. laevior n. var. PI. Ill, fig. '] a. 



Shell with the peripheral and infraperipheral keel quite or nearly smooth (in one instance 

 also the upper keel), sculpture of the umbilicus more conspicuous. 



The specimen from Stat. 260 is quite intermediate, the nodules being present on the 

 peripheral and infrasutural keels, I have distinguished it as forma intermedia. The finer sculpture 

 of the upper part of the whorls and of the base, varies also in some degree, this last one so 

 much, that it is nearly but never quite smooth. I have with much doubt, united with var. laevior^ 

 a specimen from Stat. 59, with more rounded, less deeply separated upper whorls ; as it is 

 however not in good condition, I think it ought not to be named separately. 



A young specimen of 4Y3 whorls from Stat. 253, is distinguished by its pronounced 

 sculpture, the lower whorls being crossed by plications, as however traces of plicae are present 

 on other specimens, there is no reason for separating it specifically, it may however be separated 

 as a variety under the name of: 



5° 



