193 



THE 



JOURNAL OF CONCHOLOGY. 



Vol. II. JULY, 1905. No. 7. 



PROFESSOR LANG'S BREEDING EXPERIMENTS WITH 



HELIX HORTENSIS AND H. NEMORALIS ; 



An Abstract and Review. 



By a. D. DARBISHIRE, M.A. 



(Read before the Society, March 8, 1905). 



Professor Lang's experiments^ with the above-mentioned snails 

 deserve careful study from the student of organic evolution in general, 

 because they compel him to ask himself what he means when he states 

 that Helix nemoralis and FI. hortensis are distinct species ; and from 

 the student of heredity in particular, because the results of breeding 

 different varieties of H. hortefisis are adduced as a "brilliant confirma- 

 tion of a part of Mendel's law." A knowledge of Mendelian principles 

 that will enable the reader to understand their connection with Lang's 

 results is easily acquired;^ but a clear appreciation of the nature of 

 these principles is not widely distributed. It is in the hope that 

 members of this society may start experiments and obtain results as 

 interesting as those of Professor Lang that I give some account of the 

 manner in which those experiments were carried out. 



The snails were kept in wooden boxes, whose floors were perforated, 

 the holes thus made were covered with fine wire gauze ; on the floor 

 of the box above the gauze was spread a layer, a few inches thick, of a 

 mixture of peat and wood-earth. A lid, which provided ventilation 

 but prevented the escape of the young, was formed of a horse-hair or 



1 " Ueber Vorversuche zu Untersuchungea iiber die Varietatenbildungen von Helix 

 hortensis Miiller and Helix nemoralis L." Festschrift ztim siebzigsien Geburtstage von Ernst 

 Haeckel, Jena, 1904, p. 439. 



2 W. Bateson, " Mendel's Principles of Heredity " ; A. D. Darbishire. Manchester Meinoits, 

 vol. 48, no. 24, p. 19, 1904. 



N 



