SPONGES AND ZOOPHYTES. 139 



in large quantities at once by the Stick-net, renders it a most beautiful 

 subject for observation when due scope is given to its movements; but 

 for the sake of Microscopic examination, it is of course necessary to con- 

 fine these. Various species of true Beroe, some of them even attaining 

 the size of a small lemon, are occasionally to be met with on our coasts; 

 in all of which the movements of the body are effected by the like agency 

 of paddles arranged in meridional bands. These are splendidly luminous 

 in the dark, and the luminosity is retained even by fragments of their 

 bodies, being augmented by agitation of the water containing them. 

 All the Ctenophora are reproduced from eggs, and are already quite ad- 

 vanced in their development by the time they are hatched. Long before 

 they escape, indeed, they swim about with great activity within the 

 walls x)f their diminutive prison; their rows of locomotive paddles early 

 attaining a large size, although the long flexile tentacles of Cydippe are 

 then only short stumpy protuberances. Through the embryonic forms 

 of the two groups, Prof. Alex. Agassiz considers the Ctenophora as re- 

 lated to EcJiinodermata. 



Those who may desire to acquire a more systematic and detailed acquaintance 

 with the Zoophyte-group, may be especially referred to the following Treatises 

 and Memoirs, in addition to those already cited, and to the various recent syste- 

 matic Treatises on Zoology: Dr. Johnston's "History of British Zoophytes," 

 Prof. Milne-Ed wards's " Recherches sur les Polypes," and his " Histoire des Co- 

 rallaires" (in the ' Suites a Buffon'), Paris, 1857, Prof. Van Beneden ' Sur'les Tubu- 

 laires,' and Sur lesCampanulaires.' in " Mem. de FAcad. Roy. de Bruxelles," Tom. 

 xvii., and his " Recherches sur 1'Hist. Nat. des Polypes qui frequentent les C6tes 

 deBelgique," Op. cit., Tom. xxxvi., Sir J. G. Daly ell's "Rare and Remarkable 

 Animals of Scotland," Vol. i., Trembley's "Mem. pour servir a Thistoire d'un 

 genre de Polype d'Eau douce," M. Hollard's ' Monographic du Genre Actinia,' in 

 <; Ann. des Sci. Nat." Ser. 3, Tom. xv., Prof. Max Schultze, 'On the Male Repro- 

 ductive Organs of Campanularia geniculata,' in " Quart. Journ. of Microsc. Sci.," 

 Vol. iii. (1855), p. 59, Prof. Agassiz's beautiful Monograph on American Medusae, 

 forming the third volume of his "Contributions to the Natural History of the 

 United States of America," Mr. Hincks's " British Hydro-id Zoophytes," Prof. 

 Allman's admirable Memoirs on Cordylophora and Myriothela in the Philos. 

 Transact, for 1853 and 1875, Prof. J. R. Greene's "Manual of the Sub-Kingdom 

 Coelenterata," which contains a Bibliography very complete to the date of its 

 publication, and the articles ' Actinozoa,' ' Ctenophora,' and 'Hydrozoa,' in the 

 Supplement to the Natural History Division of the " English Cyclopaedia." The 

 Ctenophora are specially treated of in Vol. iii. of Prof. Agassiz's " Contributions 

 to the Natural History of the United States." See also Prof. Alex. Agassiz " Sea- 

 side Studies in Natural History," and his " Illustrated Catalogue of the Museum 

 of Comparative Anatomy at Harvard College," Prof. James-Clark in "American 

 Journal of Science," Ser. 2, Vol. xxxv., p. 348, Dr. D. Macdonald in "Transact. 

 Roy. Soc. Edinb.," Vol. xxiii., p. 515, Mr. H. N. Moseley 'On the Structure of a 

 species of Millepora,' in "Philos. Trans.," 1877, p. 117, and 'On the Structure of 

 the Stylasteridce,' Ibid., 1878, p. 425; and on the 'Acalephce,' Prof. Haeckel's " Bei- 

 trage zur Naturgeschichte der Hydromedusen," the masterly work of the brothers 

 Hertwig, " Das Nervensystem und die Sinnesorgane der Medusen," 1878, and the 

 Memoir of Prof. Schafer ' On the Nervous System of Aurelia aurita,' in " Philos. 

 Trans.," 1878, p. 563. 



