198 Nelson on Tertiary Mollusca of Peru. 



Cuma alternata, sp. nov. 



Plate VII, figures 3, 4. 



Shell slender, fusiform ; spire elevated, turreted and pointed ; whorls 

 six or seven, convex, separated by Avell-marked sutures and orna" 

 mented by a series of rather prominent ridges, about eight to each 

 whorl. Ridges rise in the middle of each whoii into obtuse tubercles. 

 The body whorl is large, somewhat ventricose, about two-thirds the 

 length of the shell, very convex, broadest about one-fourth from the 

 top of the whorl or near the middle of the shell. Ridges on this 

 whorl are very distinct, but gradually disappear as they approach the 

 suture, and are entirely wanting over the lower half of the whorl. 

 Surface marked by raised revolving lines, arranged in two series ; 

 l)etween every two of the larger ones there are from one to five 

 smaller, nearly equal ones ; about six of the larger in the space 

 of 5 millim. Striations much larger on the lower part of body whorl. 

 Aperture oblong-oval, half as long as the shell. Outer lip with a row 

 of small, equidistant teeth, about six in the space of 5 millim., but 

 which do not extend into the interior of the shell. Columellar lip 

 smooth and overspread with callus. Canal wide, open, and reflexed. 

 Umbilicus small, reduced to a mere chink in most specimens, bordered 

 by a large well defined keel. Length 52 millim. ; breadth 33*4 

 millim. 



This species, which must have been very beautiful when living, 

 may easily be recognized by the concentric striations, which differ 

 notably from any other species known to me. Three species have 

 been described from the Panamian fauna, all of which have stronger 

 lines than the C. alternata. 



This species is distinguished from Cuma tecta Wood, by its more 

 strongly marked sutures ; by its less sharp and angular tubercles; 

 by lacking the tooth of the columellar lip ; by finer teeth on the 

 outer lip ; and by its more orbicular mouth. From Cuma Jciosqui- 

 formJs Duel., it differs in having less pointed tubercles ; by lacking 

 the loose laminje of growth which cover the sutxires of that species, 

 and by the longitudinal imbricating lines. 



Strombina lanceolata Sby. sp. 



Golumhella lanceolata Sowerby, Proc. Zool. Soc. Lond., p. 116, 1832 ; Kiener, Iconog., 



pi. 15, fig. 2. 

 Stromhina lanceolata Gar^entQY, Rep. British Assoc. 1856; Chemi, Man. de Couch. 



et pale., 1 850. 



Shell slender, fusifoi-m, and turreted; spire long and tapering; 

 whorls seven or eight, moderately convex, flattened above. Sutures 



