123 



The two following species may conveniently be included in the- 

 Section Vesperfilio, though they present in their large turbinate 

 pullus of several crenulated whorls a facies peculiarly their own. 



5. Voluta MacDonaldi, Ta^e. Plate iii., fig. 5. 



Reference. — Gastropods, Part I., plate xii., fig. 11 (1888). 



Shell oval-oblong, with a rather short gradated spire ending 

 in a subcylindrical pullus of four and a half narrow crenulated 

 whorls, the terminal ones depressed. 



Whorls three, excluding pullus; the two posterior whorls 

 angulated in the posterior-third, the front parallel with the axis 

 and costated, the posterior area concavely sloping upwards ; the 

 cost?e terminate at the shoulder in high-vaulted spinous scales ;. 

 on the first spire-whorl the spines are about 20 in number, and 

 terminate each a pair of costse. 



The body whorl is somewhat ventricose, with a high shoulder, 

 concavely sloping upwards to the suture ; the angulation crowned 

 with 16 spinous scales which terminate broad undulations, not 

 ribs, rapidly becoming obsolete. Columella with four distant 

 plaits ; outer lip thin. The whole surface is sculptured with striae 

 and growth-lines ; the only spiral-sculpture is confined to the last 

 whorl of the pullus. 



The pullus is not sharply separated from the ordinary spire- 

 whorls, as there is a gradual change in the shape and ornament 

 of the whorls ; the actual junction being somewhat indicated by 

 a slight eccentrictity of the first spire-whorls. Counting from 

 the summit, the first and second whorls are smooth, flatly convex, 

 with a deep suture, almost on a level, though the extreme tip is 

 a Little raised ; the third whorl is convex, flatted, and strongly 

 crenulated in front of the suture ; the crenulations gradually 

 elongate with the increasing angulation, so that the last is con- 

 spicuously angulated and costated, but not at all spinously pro- 

 duced ; this last whorl is marked moreover with fine spiral 

 ridges. 



Dimensions. — Total length, 115 ; breadth, 67 ; length of aper- 

 ture, 80 ; ^\adth, 130 ; height of pullus, 11 ; gi^eatest width, 13-5. 



Locality. — Lower beds at Muddy Creek (^H. McDonald) ; blue 

 clays at Schnapper Point (R.T.). 



Until I received the very handsome specimen, herewith figured, 

 from Mr. McDonald, of Hamilton, after whom I am pleased to 

 name the species, I was acquainted ^vith only two very young^ 

 specimens collected by myself at Schnapper Point, one of which 

 is figured in my Part I., as quoted above. 



