Generalia 17 



division expands each class through order and family, to genus and 

 species. Shells of genera belonging to the Amphineura, Pelecypoda, 

 Scaphopoda, and Gasteropoda are considered in this manual. 



The system of scientific nomenclature in general usage is bi- 

 nominal. Latin or Greek words are generally used for generic and 

 specific names. Occasionally proper names, names of localities, or 

 words from a language other than Greek or Latin are chosen but 

 are always given m Latmized form. 



Each genus possesses a distmctive name, always capitalized — 

 viz. Oliva. The name of a species consists of the name of its genus, 

 followed by its own distinguishing name, both in italics; next is 

 appended the name of its author whose original published descrip- 

 tion or definition clearly established the species, — viz. Oliva sayana 

 Ravenel. Variations of a species suflFiciently well defined and constant 

 to merit subspecific distinction are given a third name which is inter- 

 polated between the specific name and the name of the sponsor, — 

 viz. Oliva sayana citrina Johnson. 



An often used form of typography in connection with the 

 writing of scientific names is employed herein. If the generic name 

 has been changed from that of the original, parentheses are placed 

 around the author's name, e.g., Crassostrea virginica (Gmelin) 

 [p. 43]. Such form indicates that Gmelin did not designate his 

 species, Crassostrea, and one would not look in his work for the species 

 under that generic name. In the case of Ostrea permollis Sowerby, 

 Ostrea was the generic name originally used. Thus if the significance 

 of the parentheses is appreciated, time can be saved in reference 

 work. 



COLLECTION AND PREPARATION 

 OF SPECIMENS 



Shells of many — probably most — of the mollusks whose habitat 

 is the nearby sea bottom may be found at some time on the open 

 beaches. Shore collecting is profitable in proportion to the regu- 

 larity and persistence of the search. It will afford a considerable 

 variety of excellent specimens, and at any time a happy coincidence 

 of time and tide may bring a rare treasure to the hand of the col- 

 lector. 



