OF SANTO DOMINGO. 229 



becomes of the greatest importance to ascertain how flir it can be depended on. I 

 find that the character of this spiral ornament, when present, is of mucli greater 

 valne than the fact of its actual presence or absence. Again, in many species, espe- 

 cially in 3^onng specimens, the whole or a part of the surface may be marl^ed by 

 raised ridges or simple strife. These may be smooth, or they may bear small 

 tubercles. The presence or absence of these tubercles is usually of no importance 

 in specific determination. But raised ridges never widen so as to produce flat ribs ; 

 that is to say ribs proper are never interchangeable with regular impressed grooves. 

 In a shell which is sculptured in its young stage and smooth when old, or in a 

 variable species, sometimes sculptured and sometimes plain, it is an invariable rule 

 that the sculpture disappears first fi'om the part nearest the angle, and almost always 

 some trace of it, albeit very faint, is discernible at the anterior end. In the variably 

 sculptured species, there seems to be no connection between the disappearance of the 

 striae on the side and on the top of the whoi'l. The latter may be used guardedly 

 but a determination of cones, without the colors must be rather an adjustment of 

 averages than a dependence on fixed specific characters. Of course there are some 

 marked forms to which this statement will not apply, but it is true with reference 

 to the greater majoritj^ of the species. " - 



- ■ 3.: 



C. p y r i f 0 rmi s . Rve., Icon. Concli. sp. 70. ■ . , ■ ■ 



G. soUdus, Sby. Quart. Jour., Vol. VI., p. 45. 



G. solidm, Guppy. Quart. .Jour., Vol. XXII., p. 287, pi. IG, fig. 1. ' • ' 



G. solidus, Sby. Coucli. 111., fig. 76. 



C. recognitus, Guppy. Proc. Sci. Assn. Trinidad, 1SC7, p. 171. . 



A very common fossil, found living at Panama. I have comj)ared excellent fossil 

 specimens retaining their coloi- pattern with the recent shell and find them indentical 

 in eVery I'espect. The shape is variable, the sides of the spire are always more or 

 less concave, but the elevation of the apex changes greatly as the shell grows older ; 

 the young specimens being usually mach more elevated than old ones. The species 

 can be distinguished from all of the others by the rounded angle of the body whorl ; 

 though in two or three cases a slight angulation could be detected. 



C. c o n s o b r i n u s . Sby., Quart. -Jour., A^ol. VI., p. 45. 



C. granozoncUus, Guppy. Loc. cit.. Vol. XXII., p. 287, pi. IG, fig. 5. 



Sowerby notes the variations of this shell. I have young specimens that are 

 crossed over the entire surface with beaded linear ribs, and every iiitermediatc stage 

 to entirely smooth shells. The species can be recognized by its elevated, coronated 

 spire, and the general resemblance of its form to that of C. cedo-mdli ; C. granozo- 

 nabis, Guppy, is the young costate form of the species. 



A. P. S. — VOL, XV. OF. 



