JVelso7i on Tertiary Mollasca of Peru. 197 



Mitra, sp. ind. 



Three specimens have been found, which I refer to the same species, 

 and to this genus. The spire is very elongated. Sutures distinct, 

 whorls moderately convex. Body whorl slightly depressed and 

 angulated above. Outer lip sharp and thin. Columellar lip covered 

 by callus and furnished with four strong plaits. The two upper are 

 nearly equal in size and much larger than the lower ones. The speci- 

 mens are so badly worn and broken that it is impossible to give any 

 characters except those mentioned above. Our largest specimen, of 

 five whorls, gives as measurements : length 9 8 '2 raillim. ; breadth 

 34-2 millim. 



Marginella incrassata, sp. nov. 



Plate VI, figures 5, 6. 

 Shell large, conical, ovate, two-thirds aS wide as long, thick. 

 Spire rather short and acuminate. Sutures indistinct. Body whorl 

 regularly conical, very convex, broadest one-fourth from top, forming 

 a well rounded shoulder, and tapering rapidly from this point to end of 

 spire. Aperture linear and narrow. Outer lip with the margin thick 

 and broad. Columellar lip with four nearly equal, well developed 

 plaits; the two upper more widely separated than the lower ones.* 

 Measurements as follows : 



Young, Length, 20-60'nm Length of spire, 2 -60™™ Breadth 10-40mm 



Medium, 23-05 2-65 14-0 



Mature, 27-8 3-0] 18-6 



This large and fine species may easily be distinguished from any 

 now living on that coast by its proportionate measurements, by its 

 thicker outer lip, great prominence of the top of the body whorl, and 

 the short spire. 



Oliva, sp. ind., A. 



This genus is represented by a specimen slightly resembling 

 0. palpaster Mke., but the body whorl is less regularly convex ; pro- 

 portionally broader near the top of the whorl and hence more coni- 

 cal. Our specimen gives the following measurements: length 37*4 

 millim. ; length of spire 5*3 millim, ; breadth 19'1 millim, 



Oliva, sp. ind., B. 



A badly worn specimen differs from the preceding in having a shorter 

 spire, and the body whorl proportionally broader. N"o other charac- 

 ters observed. Length 41-2 millim. ; length of spire 3*4 millim. ; 

 breadth 24 millim. 



* The upper plait is not represented in the figure. 



