170 BUCC1NUM. 



Synoptic Table of the Species of Buccinum. 

 According to Dr. Win. Stimpson. 



A. Body-whorl angulated or carinated. 



a. Primary transverse ridges flat ; secondary ridges inconspicuous. 



1. Shell thin ; aperture not patulous ; outer lip not sinuated. 



* Whorls shouldered; aperture broadest above. B.POLARE. 



* * Whorls scarcely shouldered ; aperture broadest below. 



B. GRCENLANDICUM. 



2. Shell thick and strong ; aperture patulous ; outer lip sinuated. 



* Shell elongated. B. DONOVANI, 



* * Shell ovate. B. GLACIALE. 



b. Primary transverse ridges convex ; secondary grooves very dis- 



tinct. B. ANGULOSUM. 



B. Body- whorl not angulated. 



a. Aperture narrow. 



1. Primary ridges flat. B. STRIATUM. 



2. Primary ridges convex ; a strong tooth-like plait on the 



columella. B. CILIATDM. 



6. Aperture broad. 



1 . Longitudinal folds numerous, often interrupted or interposed. 



* * Primary ridges flat. B. PLECTRUM. 



* * Primary ridges obsolete ; secondaries conspicuous, 



crowded. B. TENTJE. 



2. Longitudinal folds not interrupted or interposed. 



* Shell thick and coarsely striated. 



f Sinus of outer lip near the suture, columella short. 



B. UNDULATUM. 



f t Sinus of outer lip near the middle, columella pro- 

 jecting. B. UN DATUM. 



* * Shell finely striated, usually thin. 



f Secondary ridges easily distinguished from the 



primaries, which are often obsolete. 

 || Columella distinctly folded. B. SIMPLEX. 



|| || Columella smooth, not distinctly folded. 



B. CYANEUM: 



ft Secondary ridges confounded for the most part 

 with the primaries 



I Longitudinal folds conspicuous. B. TOTTENI. 

 || I Longitudinal folds obsolete. 



B. HUMPHREYSIANUM. 



Since the preparation of my manuscript on Buccinum^ Dr. J. 

 Gwyn Jeffreys has published a paper upon their synonymy, 

 which, in view of his discriminative ability and experience with 



