544 FBANK E. BEDDARD. 



two penial setse may be often seen protruding from the 

 orifice. 



I found no genital papillae of any kind. 



IV. Anatomy and Histology. 

 § Body-wall. 



Epidermis. — The chief point to be noted about the epi- 

 dermis is the absence of the peculiar sense organs so generally 

 found among the Eudrilidae. I have described them in 

 Eudrilus, Hyperiodrilus, and Heliodrilus. Dr. Horst 

 has recently described them in an African species of Eudrilus, 

 and was the first to suggest that they were possibly sense 

 organs j he compares them to the Pacinian bodies of Verte- 

 brata. I had originally considered these bodies as repre- 

 senting rudimentary setae, and as corresponding to those 

 epidermal structures in Urochaeta which Perrier first de- 

 scribed, and considered as rudimentary setae ; but a more 

 detailed examination of their structure led me to express in 

 my paper upon Hyperiodrilus and Heliodrilus an 

 opinion that they were of a sensory nature, and to make the 

 identical comparison that Dr. Horst made, previously in point 

 of time of publication. Rosa has found these structures in 

 Teleudrilus; but they do not exist in Nemertodrilus or 

 in Libyodrilus. The absence of these epidermal sense 

 organs unites these two genera, which have other points in 

 common. 



The cells of the epidermis are of the usual kind ; the large 

 glandular cells appear to be perhaps unusually abundant. I 

 have not made a special study of the histology of the epi- 

 dermis, which has been recently so elaborately worked out 

 and 80 beautifully illustrated in Lumbricus by M. Cerfon- 

 taine (8). 



Muscular Layers. — The usual circular and longitudinal 

 muscles are present ; the relative thickness of the two coats 

 may be judged from figs. 4 and 13. In both layers the fibres 



