ON THE DEVELOPMENT OF TUBULIPORA. 151 



" alveoli/' which are at first distinct from the cavity of the 

 ovicell. The lobes of the ovicell, and even of the embryophore, 

 unite with one another on the distal side of the zooecia, which 

 thus pass through the cavitj' of the ovicell as completely free 

 columns. 



Further investigations will be necessary in order to ascertain 

 how far the distinction of genera and species of Cyclostomes 

 can be based on the characters of the ovicells. 



References. 



1. Barrois, J. — " Uecherclies sur I'Embryologie des Brvozoaires," Lille, 



1877. 



2. Busk. G. — " Cat. of the Cyclostomatous Polyzoa in the British 



Museum," 1875. 



3. Busk, G.— " Challenger Reports," parti ("Polyzoa," II), 1886. 



4. Claparede, E. — "Beitrage zur Auat. u. Eutwicklungsgeschichte d. 



Seebryozoen," 'Zeits. f. wiss. Zoo!.,' xxi, 1870, p. 137. 



5. Couch, R. Q. — "A Cornish Fauna," part iii, Truro, 1844. 



6. Dalyell, Sir J. — " Rare and Remarkable Animals of Scotland," ii, 1848. 



7. Davenpokt, C. B. — "Observations on Budding in Paludicella and some 



other Bryozoa," 'Bull. Mus. Comp. Zool.,' xxii, 1891-2, p. 1. 



8. EisiG, H. — " Monogr. d. Capitelliden," ' Fauna u. Flora G. v. Neapel,' 



xvi, 1887. 



9. Ellis, J. — "An Essay towards a Natural History of the Corallines," 



1755. 



10. Ellis, J., and Solander, D. — " The Natural History of Zoophytes," 



1786. 



11. Fabricius, 0. — " Fauna Groenlandica," 1780. 



12. Gregory, J. W. — " Cat. of the Fossil Bryozoa in the British Museum," 



1896. 



13. Harmer, S. F. — " On the British Species of Crisia," ' Quart. Journ. 



Micr. Sci.,' xxxii, 1891, p. 127. 



14. Harmer, S. F. — " On the Nature of the Excretory Processes in Marine 



Polyzoa," ' Quart. Journ. Micr. Sci.,' xxxiii, 1892, p. 123. 



15. Harmer, S. F. — " On the Occurrence of Embryonic Fission in Cyclosto- 



matous Polyzoa," 'Quart. Journ. Micr. Sci.,' xxxiv, 1893, p. 199. 



