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 alimentarj'. 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 Oligochseta. 



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. £. — "Geographical Distribution." Proc. Zool. Soc, 1893, p. 733. 



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



3. "Embryology of Octochcetus." Quart. J. Micr. Sci., xxxiii., 



P- 495- 



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



5. " Hespeiodrilus." Ann. Mag. Nat. Hist., Feb., 1894. 



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



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



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



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



10. Bourne, A. G. — " Development of Perichata." Quart. J. Micr. Sci., May, 1894. 

 II. "Naids." 7i/rf., xxxii., p. 335. 



12. Levinsen, G. — " Digit ibranchus." Vidensk. Med., i88g, p. 318. 



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



14. Hesse.^" Enchytrasida." Zeitsch. wiss. Zool., 1893. 



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



16. . — "Development of Megascolides." Arch. mikr. Anat., xxx., 



P- 552- 



F. E. Beddard. 



