THE NAUTILUS. 



Vol.. XXII. JULY, 1908. No. 3. 



ON EUCONULUS FULVUS AND E. TROCHIFORMIS. 



BY HENRY A. FILSBRY. 



Helix fulva as described by Miiller (1774) was a composite of two 

 species: (1) adult Helix fulva of Draparnaud and later authors, and 

 (2) immature Helix bidentata Gmelin. Miiller's idea exactly re- 

 versed the age-relations of the two forms; he considered (1) to be 

 the young stage of (2), and while he described both forms satisfac- 

 torily, and gives the measurements of both, a fuller description is 

 naturally given of the form he considered adult. The somewhat 

 unusual conic shape, etc., rendered it easy for subsequent authors to 

 recognize both forms from Muller's description. Indeed it would 

 be hardly possible to mistake any other snail of the region for either. 



The next notice of the forms was by Gmelin (1701), who admits 

 Muller's H. fulva without recognizing its composite nature, his ac- 

 count being merely compiled from Miiller. Gmelin moreover de- 

 scribed and named the adult stage of Helix bidentata, referring to 

 unmistakable figures in the Conchylien Cabinet of Chemnitz. There 

 has never been any controversy about the validity of Grnelin's H, 

 bidentata. 



Ten years later (1801), Draparnaud, in his Tableau des Moll, 

 terr. etfluv. de la France, p. 72, restricts Helix fulva to the Eiiconu- 

 lus, giving an excellent description. He also recognized and de- 

 scribed H. bidentatu, the two being quite rightly placed in different 

 groups. Up to the present time this arrangement has been followed 

 almost universally. 



