CLASSIFICATION OF CTENOPHORES. 95 



Order 2. Saccatce. Body more or less spherical, with two long tenta- 

 cles capable of being wholly retracted in a sac (Pleuro- 

 brachia). 



Order 3. Tceniata. Body ribbon-like, being very much compressed in 

 the direction of the lateral diameter (Cestum). 



Order 4. Lobattz. Body lateral, compressed, bilobed (Bolina). 



VIEW OF THE CLASSIFICATION OF THE CTENOPHORA. 



Lobata. 

 (Bolina.) 



Tcem'ata. 

 (Cestum.) 



Saccata. 

 (Pleurobrachia.) 



Eurystomea. 

 ffdyia.) 



CTENOPHOKA. 



Laboratory Work. The Ctenophorse should be studied while alive. 

 They may be collected with a drag or tow-net from a boat when the 

 surface of the ocean is calm. For studying the fine anatomy and 

 tissues they should be treated by the same methods as the smaller jelly- 

 fishes. 



LITERATURE. 



L. Agassis. Contributions to the Natural History of the United 

 States. IIL-IV. 1860-1862. 



Dana. Report of U. S. Exploring Expedition. Zoophytes. 1846. 



Huxley. The Oceanic Hydrozoa. Ray Society, London, 1859. 



M. Edwards and Haime. Histoire naturelle du Corail. i.-iii. Paris, 

 1857-1860. 



Lacaze-Duthiers. Histoire naturelle du Corail. Paris, 1864. 



Haeckel. System der Medusen. Jena, 1880-1881. 



A. Agassiz. North American Acalephae. Mem. Mus. Cornp. 

 Zool. Cambridge, v. 1865. 



A. Agassiz. Embryology of the Ctenophorae. 1874. 



Kleineriberg. Hydra. Leipzig, 1872. 



"With the works of A. Agassiz, Allman, Andres, H. J. Clark, 

 Claus, Ehrenberg, Gegeubaur, Gosse, O. and R. Hertwig, Hiucks, 

 Huxley, G. von Koch, Koelliker, Leuckart, Metschnikoff, Moseley, 

 Sars, Semper, Vogt, Weismanu, Wilson, etc. 



