52 NATURAL SCIENCE. July, 1894. 



formed of a much-folded membrane, had, as it were, melted into a 

 solid ball. But the peculiar relation of the cells to blood-vessels seems 

 to suggest a changed function, connected rather with the vascular 

 system than with the alimentar}'. The whole matter is one of great 

 interest, but would need for its proper discussion some space, which 

 could not be fairly occupied by an article professing only to give a 

 sketch of some of the more important recent advances in our know- 

 ledge of the structure of the Oligochaeta. 



The bibliography which follows is, of course, not exhaustive of 

 the last two years ; I have merely quoted those papers to which I 

 have especially referred. 



REFERENCES. 

 I. Beddard, F. E. — " Geographical Distribution." Proc. Zool. Soc, 1893, p. 733. 



2. " j^olosoma." Ann. and Mag. Nat. Hist., Jan., 1892. 



3. " Embryology of OctocJiatus." Quart. J. Micr. Set., xxxiii., 



P- 495- 



4. " Lybiodriliis." Ibid., xxxii., p. 539. 



5. ■ — " Hesperodrilus." Ann. Mag. Nat. Hist., Feb., 1894. 



6. " Sntroa." Trans. Roy. Soc. Edin., 1892, p. 195. 



7. Benham, W. B. — " Classification." Quart. J. Micr. Sci., xxxi., p. 201. 



8. Eisen, G. — " Sutroa." Zoe, vol. ii., p. 321. 



9. Rosa, D. — " Paradrilus." Ann. k.k. Hof. mus. Wien, vi., p. 379. 



10. Bourne, A. G. — " Development oi Perichceta." Qitart. J. Micr. Sci., May, 1894. 

 II. "Naids." /i/(f., xxxii., p. 335. 



12. Levinsen, G. — " Digitibranchus." Vidensli. Med., 1889, p. 318. 



13. Cerfontaine, A. — " Structure of Lumbricus." Arch. Biol., x., p. 327. 



14. Hesse. — " Enchytraeida." Zeitsch. K'iss. Zool., 1893. 



15. Vejdovsky, F. — " Entwickelungsgeschichtliche Untersuchungen," Prag. 



16. . — "Development of Megascolides." Arch, mi/ir. Anat., xxx.^ 



P- 552- 



F. E. Beddard. 



