The Nautilus. 



Vol,. XVII. NOVEMBER, 1903. No. 7. 



SOME NOTES ON THE GENUS FULGUR. 



BY CHAS. W. JOHNSON. 



In the very interesting and valuable paper, " Studies of Gastro- 

 poda II, Fulgur and Sycotypus," by Amadeus W. Grabau (Amer. 

 Naturalist, August, 1903), the author has again brought to generic 

 rank the name of Sycotypus. No stronger evidence is brought forth 

 to uphold this view than that already given, viz., the character of the 

 protoconch, as pointed out by Conrad. Dr. Dall and others consider 

 the condition of Conrad's specimens to have been pathologic, while 

 the many tertiary forms seem to completely bridge all distinguishing 

 conchological characters, leaving only the ciliated periostratum, a 

 feature which is lost in the fossils and in Fulgur pyrum is often obso- 

 lete or wanting. Still Sycoly/jus, as a rule, forms a recognizable 

 group, very convenient in tracing the origin of many of the species. 



Has the protoconch of F. pyrum been studied ? It may have no 

 bearing on the subject, but it is interesting to note that while the 

 egg-capsules of F. canaliculatum are readily distinguished from F. 

 cdrica and F. perversum by having a single-keeled edge, those of F. 

 pyrnm are biangular, resembling those of F. perversum in miniature. 



In tracing the ancestral relations of the various so-called species, 

 Mr. Grabau has brought out many points which deserve careful con- 

 sideration. Every one who has made a study of the tertiary species 

 probably l^as a different view in regard to the relationshii) of tlie 

 various forms, and these views should be freely given and the con- 

 sensus of opinion adopted. 



All agree that the Eocene Levifusus is probably the immediate 



