THE NAUTILUS. 1 U 



Its continental area, its diversity of climate from the lioreal re- 

 gions of the British possessions to the very borderland of the tropics, 

 its wide streches of plains, varying from forest covered to entirely 

 naked, the difference in the height of its mountains, its areas of 

 almost perpetual humidity which shade out into desert regions, 

 would give just the conditions necessary for the wide distribution of 

 species, and for great and gradual variation. Such wide distribu- 

 tion and variation we find with most of our forms of mollusks. 



Various methods have been proposed by which these lesser varia- 

 tions may be designated. Some have classed them as varieties of 

 species, giving to each a varietal name, others have resorted to let- 

 tering or numbering, while the ornithologists of America class them 

 as sub-species. The New School of Conchologists of Europe seeks 

 a way out of the difficulty by applying specific names to a great 

 many of the minor variations, and generic names to small and ill- 

 defined groups of species. Unfortunately for such systems of nomen- 

 clature, variation does not always occur in a lineal direction, or in 

 other words, from one genus or species directly to another, but often 

 seems to be broken up so that certain forms or groups combine the 

 characters of several other forms or groups, and appear very much 

 like hybrids. 



In the wonderful series of Patula, beginning with elevated shells 

 with rounded whorls and strong radiating ribs known as Helix Ida- 

 hoensis which vai'ies gradually through the less elevated and smoother 

 forms of Cooperi and strigosa, to HeviphiUi and Haydeni which are 

 lenticular and sharply keeled with strong revolving sculpture, we 

 find such irregular varieties or natural hybrids, which hardly admit 

 of naming. Elevated forms are not rare, having radiating sculp- 

 ture and sharp keels, in others of the same general form the ridges 

 are revolving, thus partaking more or less of the characters of Ida- 

 hoensis and Hemphini ; and greatly flattened shells are met with, 

 without keels and with more or less decussated or even radiating 

 sculpture, in fact in the 1500 or more sjiecimensof this protean form 

 in the collection of the National Museum, one can observe this 

 crossing of characters in almost every direction. To attempt to 

 designate these hybrids, if such they are, by name is simply an im- 

 possibility. The argument is p*ut forth by many that it is better to 

 give any form a name than to have to describe it every time, it is 

 mentioned, but to carry it out one could apply fifty names to the 

 variations oi Melongena corona or Cyrena Floridana, or twice that 



