THE SENSE-ORGANS OF LUMBRICUS 

 AGRICOLA, HOFFM.i 



FANNY E. LANGDON. 



In December of 1891, sections of Lumbricus agricola, 

 Hoffm.2 were prepared in the Laboratory of Animal Morphol- 

 ogy of the University of Michigan, in which the epidermal 

 cells presented in many places an arrangement similar to that 

 which is found in the vertebrate "taste-buds." At the sugges- 

 tion of Prof. J. E. Reighard, the writer and Miss M. F. Ran- 

 dolph undertook an examination of the literature and a study 

 of the structure, nerve-supply, and distribution of these appar- 

 ent sense-organs. Soon after this, there appeared a paper by 

 Lenhossek ('92), in which it is stated that the sensitiveness of 

 Lumbricus is due to isolated nerve-cells scattered through the 

 epidermis, and that these nerve-cells are never grouped into 

 sense-organs. An examination of the literature brought out 

 the fact, not referred to in Lenhossek's paper, that epidermal 

 sense-organs had already been seen and described by Leydig 

 ('65), Mojsisovics ('77), Vejdovsky ('84), Ude ('86), and Cerfon- 

 taine ('90), in Lumbricus agricola, and in other species of Lum- 

 bricidae. Our work then resolved itself into an attempt to 

 determine accurately the facts at first hand in order to under- 

 stand the conflict between the account of Lenhossek and the 

 accounts of earlier writers. As Miss Randolph did not return 

 to the University the next year, I have since carried on the 

 work alone. 



For the sake of clearness, I shall give first a continuous 

 account of my own observations, and shall reserve until the end 

 of the paper all discussion of the work of others, 



^ Work from the Laboratory of Animal Morphology of the University of 

 Michigan, under the direction of Prof. J. E. Reighard. 



2 This species, upon which all my work has been done, has the characteristics 

 of L. herculeus, Sav. as given by Ude ('86). 



