196 Nelson o?i Tertiary Mollusca of Peru. 



Malea, sp. ind. 



I refer, very doubtfolly, to this genus three casts, which resemble 

 somewhat the young of 31. ringens Sby. Further specimens are 

 necessary to settle their relations accurately. 



Argobuccinum Zorritense, sp. nov. 



Plate VII, figures 1, 2. 



Shell slender, ventricose ; spire elevated, conical ; whorls about 

 seven, moderately convex, and depressed above. Sutures distinct, but 

 not deeply impressed. Surface marked by strong, flattened revolving 

 ribs, varying in width. Spaces between the ribs well marked, as 

 wide or wider than the ribs (except on the body whorl), smooth, 

 or ornamented with fine revolving lines. Upper ribs of each 

 whorl somewhat nodulous, forming a more or less distinct shoulder. 

 Body whorl large, more than half the length of the shell ; ribs 

 wider than the spaces between them ; upper ribs forming a dis- 

 tinct shoulder, depressed above, and forming a strong angulation with 

 the rest of the shell ; lines of growth strong, giving to the whorl 

 somewhat of a cancellate appearance. Aperture oblong, regularly 

 ovate, and broadest just above the center, one-third as long as the shell. 

 Outer lip sharp and having within numerous teeth, extending 

 well into the interior of the shell, nearly equidistant, about one- 

 fourth as wide as the spaces between them, and ten in the space of 

 5 millim. Columellar lip covered thinly by callus, which is thickened 

 below into a distinct ridge. Umbilicus wanting. Umbilical keel 

 strong and rugose. Canal open, short and reflexed. A large speci. 

 men measures: length 51*2 millim.; breadth 29 millim. A smaller 

 specimen gives the following measurements: length 35*4 millim.- 

 length of spire 18 millim. ; breadth 19 "2 millim. 



This species, one of the finest of the whole collection, is very abund- 

 ant, especially in the condition of casts. One cast measures : length 

 59 millim., by breadth 30 millim. On all mature specimens the 

 nodulous character of the top of each whorl is very characteristic. 

 On the body whorl these nodules rise into obtuse tubercles, about ten 

 or twelve to the whorl. In mature specimens, also, the lower whorl is 

 produced in front, having its greatest width near the central line of 

 the whorl, and causing the aperture, when viewed obliquely, to 

 appear somewhat quadrilateral. Young specimens differ in lacking 

 the teeth of the outer lip, and the tubercles of the body and adjacent 

 whorls. 



