153 



GASTEROPODA. 



METOPTOMA ALCESTE. (N. sp.) 



Fig. 133, a, b. 



Description. Shell conical or sub-pyramidal ; base sub-ovate or sub- 

 circular, broadly rounded in front, sides gently convex, anterior margin 

 with a small space in the middle nearly straight. Apex at about one 

 fifth the length from the anterior margin, much elevated, the anterior side 

 gently convex or nearly flat with a strong rib running from the apex to the 

 middle of the front margin. This is the appearance of the fossil as seen 

 in the cast of the interior, no specimens with the shell preserved having 

 been collected. 



Length of base of large specimen 13 lines ; width about the same ; 

 height 14 lines. In some specimens the greatest width is about one third 

 the length from the anterior margin, but in others it is a little in advance 

 of this position. 



The rib in this species resembles that so frequent in species of Belle- 

 rophon, and it may be that the side which is called anterior in these de- 

 scriptions is the posterior side. 



Locality and Formation. English Head, Anticosti ; in the Hudson 

 River group. 



Collector. J. Richardson. 



METOPTOMA ESTELLA. (N. sp.) 



Fig. 133. Fig. 134. 



o ** 



Fig. 1^3. Metoptwna dlcesie. a, side view ; b, anterior view. 

 134. M. Estella. a, side, and 6, vertical view. 



Description. Base very nearly circular, length slightly exceeding the 

 width ; apex pointed, depressed or slightly incurved so that the point of it 



