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Ceritiiium modestum. Shell conic, turrited, sinistrorsal : reddish 

 black, weathering to a cinereous color : with, on the upper whorls, 

 two, and on the middle and lower whorls three spiral ridges, which 

 are of equal size on the lower two-thirds of the shell ; and numerous 

 transverse ridges, the intersections being well developed nodules ; 

 anteriorly with two or three additional spiral ridges, which are less 

 strongly nodulous, and which are separated by a broad groove from 

 a small ridge around the base of the canal : apex very acute : spire 

 with the outlines quite curvilinear : whorls about fourteen, planulate. 

 with the place of the suture distinguished by a somewhat larger groove; 

 last whorl abruptly terminating : canal short, slightly turning to the 

 right. 



Mean divergence about 23° ; length .225 inch ; breadth .07 inch. 



Ceritiiium melanura. Shell like that of C. modestum, but snow 

 white except the dark brown apex, much more slender, with the out- 

 lines less curvilinear, and the aperture smaller. 



Mean divergence about 17°; length .2 inch; breadth .045 inch. 



Cerithium decoratum. Shell conic, turrited, siuistrorsal : white, 

 dark reddish brown anteriorly, with many large rather square irregu- 

 lar spots of the same : with, on the upper whorls, two, and on the 

 middle and lower whorls, three nearly equal spiral ridges, which are 

 nearly concealed by numerous large nodules, that are produced by 

 the excessive development of the intersections of twenty-five to twenty- 

 eight small transverse ridges on each whorl ; anteriorly with two ad- 

 ditional smaller or less strongly nodulous spiral ridges : apex very acute : 

 spire with the outlines nearly rectilinear : whorls sixteen, planulate, 

 with the place of the suture distinguished by a deeper groove; last 

 whorl terminating very abruptly, so as to be concave between the 

 periphery and the canal : aperture ovate-orbicular, modified a little 

 by the penult whorl : canal strongly bent to the right, closed except 

 near the extremity. This shell resembles C. ornatum Desk., but that 

 species has only ten or twelve whorls, its outlines are quite curvi- 

 linear, and the last whorl terminates less abruptly. 



Mean divergence about 20° ; length .29 inch ; breadth .085 inch. 



Cerithium dealbatum. Shell like that of C. decoratum, but 

 snow white ; the outlines of the spire are- exactly rectilinear; the 

 granules are less developed ; and the canal is nearly straight. 



Cerithium nanum. Shell conic, turrited, siuistrorsal : wax brown, 

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