CEEITHIUM. Panama Shells. 151 



irregular linear spots of white on the spiral keels : with three 

 excessively prominent compressed acute nearly equal and equi- 

 distant spiral keels, with narrow deep interspaces, which are 

 crossed by microscopic raised lines, with a fourth keel on the 

 periphery of the last whorl, and another anteriorly which is 

 more minute : apex acute : spire with the outlines nearly recti- 

 linear : whorls sixteen to eighteen, planulate, with the suture 

 very indistinct : last whorl very short : aperture ovate : labrum 

 deeply scalloped by the spiral ridges : canal large, very short. 



Mean divergence about 18 ; length .23 inch ; breadth 

 .06 inch ; length of spire .19 inch. 



This species is allied to 0. trilineatum Phil, and to C. terebel- 

 lum Ad. 



Station. Under stones, sponges, and marine plants, &c., near 

 low water mark. 



Habitat. Panama ; C. B. A. ! 

 Eight specimens were collected. 



195. Cerithium foimargmatum. Nov. sp. 



Shell long, conic : wax color, dark brown on the upper 

 whorls : with a spiral ridge at each margin of the whorls of the 

 spire and an intermediate raised line ; on each whorl with about 

 eighteen transverse small ridges with intersections strongly 

 nodulous ; with -a simple spiral ridge at the periphery of the 

 last whorl; anteriorly without sculpture: apex very acute: 

 spire with the outlines rectilinear : whorls thirteen, concave, with 

 a well impressed suture ; last whorl very short, concave ante- 

 riorly, with the periphery angular: aperture subquadrate: 

 columella with a very prominent spiral fold : canal rather short, 

 recurved. 



Mean divergence about 20 ; length .175 inch ; breadth .055 

 inch ; length of spire .14 inch. 



Station. Unknown. 



