THE NAUTILUS. 



VOL. XXIV. SEPTEMBER, 191O. No. 5 



SOME NOTES ON THE OLIVIDAE. 



BY CHARLES W. JOHNSON. 



I. 



Perhaps no group of shells presents such a great variation of color 

 as occurs in many species of the genus Oliva. In trying to define 

 the true relative position of the various forms, two conditions act as 

 impediments the confusion in nomenclature and the lack of posi- 

 tive localities for the species. Localities for species are frequently 

 cited which are undoubtedly erroneous. That many of the forms 

 represent only local races is apparent from the fact that where speci- 

 mens have a positive habitat within the range of a species, there is 

 as a rule an apparent uniformity of the specimens which readily dis- 

 tinguishes them from others. This can perhaps be reasonably ac- 

 counted for when we take into consideration their distribution and 

 habits. Chiefly tropical and living on the sandy shores and bars of 

 the more sheltered and shallow waters of the gulfs and bays, their 

 distribution is necessarily restricted, thus creating environmental 

 conditions, favorable for numerous local variations. The necessity 

 for studying the species faunologically is therefore evident, and if 

 monographers had done so, a much clearer idea of the relationship of 

 species and the range of specific variation would have been attained. 



Tryon's views as to synonomy are most excellent, the chief fault 

 of his work being his disregard of priority, even of the Lamarckian 

 species. The excellent and numerous figures by Marrat (Sowerby's 

 Thesaurus Conchyliorum, vol. iv) illustrate practically all important 



