172 



MURCHISONIA ALEXANDBA. (N. p.) 



MURCHISONIA VENTRICOSA (Salter). Dec. 1, p. 23, pi. 5, fig. 2. 



Description. Shell rather large, turbinate, acutely conical ; apical 

 angle from 45 to 50 ; whorls about six, strongly ventricose, with a flat 

 band in the upper third. The aperture appears to be large and ovate ; 

 the inner lip is thin and folded over so as to conceal the minute umbilicus* 

 Surface finely striated. Length about 30 lines ; width of body whorl 15 

 lines. 



This species is about the size and somewhat of the shape of M. lellidncta. 

 The principal difference is in the form of the upper part of the whorl. The 

 lower two-thirds or three-fourths of the whorl is nearly uniformly convex, 

 but the upper third descends abruptly to the deep suture. The band is 

 quite flat, and being situated on the upper sloping part, gives to the whorl 

 a truncated appearance. The lower edge of the band is defined by a 

 small acute carina, seldom visible in specimens which are worn. 



In M. ventricosa (Hall) the whorls are strongly angulated in the middle, 

 as in M. perangulata. 



Locality and Formation. Pauquette's Rapids, on the Ottawa River ; 

 Black River limestone. 



Collector. Sir W. E. Logan. 



METOPTOMA SUPERBA. (N. sp.) 





Fig. 155. 



Fig. 155. Metoptoma superba. Side yiew of a specimen wticb corf',e with small 

 concretions of silex, the interior being perfectly empty. The line, b, shows 

 the form of the aperture. 



Description. Shell large, depressed conical ; aperture circular ; apex 

 central, or very nearly so. An obscure carination runs from the apex to 



