Monograph of the Cones of JYorih America. 121 



Art. XIII. Monograph of the Cones of North America, inclu- 

 ding three new species— By Jacob Green, M. D., Professor of 

 Chemistry in Jefferson Medical College, Philadelphia, Corres- 

 ponding Member. 



The genus Conus derives its name from the conical shape of the 

 shells which it embraces. It may be considered a natural associa- 

 tion of species— for though they arc exceedingly numerous, their 

 similarity in form renders it scarcely possible for the merest tyro 

 ever to mistake them. It appears to have been first established by 

 Linne, and it still remains precisely as he left it, notwithstanding 

 the numerous changes which the science of conchology has suf- 



Many of the shells of this genus are extremely beautiful, from 

 the diversity and richness of their markings. They are the diamonds 

 or gems of conchology, and therefore the rarer species are among 

 the most costly articles of the cabinet. As examples, we may no- 

 tice the Conus gloria-maris and the Conus cedc-nulli ; a very few 

 perfect examples of which have ever as yet been discovered. As 

 the strong influence of light seems to be necessary for the rich- 

 ness and variety of colour in the animal kingdom, we are not to 

 expect, and have certainly not found, any beautiful species of the 

 cone in the northern parts of America. 



All the shells of this genus have the whorls or convolutions flat- 

 tened, and rolled over each other ; the lower part or base termina- 

 ting in an obtuse point, the upper part or spire being expanded. 

 The outer whorl only is therefore entirely visible, and the other 

 convolutions are only seen at their upper edges, with a suture or 

 groove between them : these form the spire. This spire is either 

 flat or convex, or more or less produced ; and in a few instances 

 it is even slightly concave. The upper edges of the whorls are 

 either smooth or carinated : the aperture is long and narrow ; 

 effuse at the base, and never toothed ; its upper part terminates in 

 a notch occasioned by the separation of the external whorl, from 

 the others, in that place : the outer lip, in perfect specimens, is al- 

 ways smooth and sharp. The conical contour ofthese shells is 



others it is short and wide ;°the surface is sometimes covered with 

 granulations ; sometimes marked with grooves and stria?, and 

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