CLASS II. 

 POLYPS. (POLYPI) 1 . 



POLYPS are gelatinous, oblong or conical animals with a con- 

 tractile body, an intestinal cavity and an oral aperture, which is 

 surrounded by a circlet of arms or tentacles. 



Besides these arms there are no special organs of sense, at least 

 in the greater number of Polyps, though all appear to be very sensi- 

 ble of the stimulus of light. Propagation is effected partly by eggs, 

 partly by germs or buds : in many instances the last are not de- 

 tached from the parent stem, and thus there arise compound animals, 

 different individuals being connected. 



Our Polyps were, for the most part, unknown to the ancients : 

 and under this name entirely unknown. By it they understood 

 naked molluscs of the form of sepia, especially that genus which 

 is now called Octopus 2 by Zoologists. From analogy, and from 

 some resemblance of form, REAUMUR and JUSSIEU first gave the 



1 Of the numerous works on this class we are content to quote the following : 



A. TREMBLE Y, Memoirespour scrvir a I'Histoire d'une genre de Polypes d'eau douce, 

 a bras en forme de cornes. Leide, 1744, 4^o. 



J. ELLIS, An Essay towards a Natural History of the Corallines and other Marine 

 Productions, &c. Lond. 1755, 460, with plates. 



J. ELLIS and D. SOLANDER, The Natural History of many curious and uncommon 

 Zoophytes, with 62 plates. London, 1786, 4to. 



P. S. PALLAS, Elenchus Zoophytorum. Hagse Comitum, 1 766. 



F. CAVOLINI, Memorieper servire alia storia de' Polipi Marini. Napoli, 1785, 4to. 

 E. J. C. ESPEE, Die Pflanzenthiere in AlUldungen nach der Natur. in. Thle. 



Nuraberg, 1761 1797 (with two supplements). 



W. KAPP, Ueber diePolypen im Allgemeinen und dieActinien insbesondere. Weimar, 

 1829, m. 3 color. Kupfertafeln, 4to. 



C. G. EHRENBERG, Die Coralknthiere des rothen Meeres. Physilcalische Abhand- 

 lungen der Konigl. Alcad. der Wissenschaften zu Berlin aus dem Jahre 1832, s. 225 

 380. (Also published separately, Berlin, 1834, 4to.) 



G. JOHNSTON, History of British Zoophytes. Second edition, with numerous illus- 

 trations on copper and wood, i vols. 8vo, 1847. 



3 The French name Poulpe now given to this animal is merely a corruption of the 

 ancient name Polypus. 



