Vol. LIII 



August, 1927 



No. 2 





BIOLOGICAL BULLETIN 



ANATOMY AND FUNCTION OF THE REPRODUCTIVE 

 SYSTEM IN THE SNAIL, LYMNJEA STAGNALIS 



APPRESSA SAY. 1 



EDWARD DRANE CRABB, 



DEPARTMENT OF ZOOLOGY, UNIVERSITY OF PENNSYLVANIA. 



INTRODUCTION. 



Since the work of Baudelot ('63) is apparently the only avail- 

 able source of information on the finer anatomy of the reproduc- 

 tive system of the European pond snail, Lymnaa stagnalis Lin., 

 and since no definite description of the confluence of the her- 

 maphrodite duct with the male and female conduits has been found 

 for the American sub-species, L. s. apprcssa Say, it was deemed 

 advisable to undertake to describe this system in the latter form in 

 the hope that the effort would contribute to the solution of the 

 general problem of reproduction in hermaphroditic fresh-water 

 snails. Elsewhere the writer has given the results of his investiga- 

 tion of this problem by genetical (Crabb, '270) and cytological 

 methods (Crabb, '27^7). In the former paper it is shown that the 

 distinguishing characters were not inherited, but in the latter paper 

 it is shown that self-fertilization is the normal mode of reproduc- 

 tion in isolated L. s. appressa Say. 



It is interesting to note that the anatomy of the gastropod re- 

 productive system was not understood until well into the nine- 

 teenth century. Baudelot ('63) points out that Muralt, 1677, 

 Redi, 1684, Lister, 1694, Swammerdam, 1737, Cuvier, 1802-09, 

 Owen, 1825, and several others published descriptions of the re- 

 productive system of various hermaphroditic gastropods in which 



1 Contribution from the Zoological Laboratory of the University of 

 Michigan. 



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