36 C(ELENTERATA. 



rical masses, is typical of this order, of which only one genus is 

 known ; its polypes are violet or grass-green in colour. 



Tubiporidcs. 

 Tubipora. 



Order V. PENNATULACEvE. 



Polypary free, the basal end without polypes, the upper end 

 generally variously branched and bearing the polypes. 



The polypes or zooids are mostly of two kinds, one set being 

 sexually developed, the other set sexless. These are borne on the 

 upper part of a fleshy ccenosarc, provided with a horny flexible 

 internal axis. 



These organisms mostly live with one end stuck deeply in the 

 mud ; but the Pennatulidse are free, moving, however, languidly, 

 and do not swim. Among the few British species one, known as 

 the " sea-pen" (P ennatul a phosphor ea), is highly phosphorescent, 

 and so probably are the entire group ; its ova are carried at the 

 back of the pinna. 



UmbeUularia has a rod-like axis six feet in length, with a tuft 

 of polypes at its apex. It is quite an aberrant form. 



Pennatulidae. Scytalium. Renillida. 



Pennatula. Pavonaria. -Remll*. 

 Pteroeides. j^ ^-//-j 

 Sarcoptilus. * eretillida. Cophobelemmdce. 



V 7 ~* yeretillum. Cophobelemnon. 



Virgularndce. Lituaria. 



Yirgularia. 



Tjmbellulana. 



Class TV. CTENOPHORA. 



ClLIOGRADA. 



Gelatinous, transparent organisms, swimming by means of rows 

 of cilia, mostly disposed in comb-like plates [ctenophores]. No 

 corallum. Hermaphrodite. 



The ctenophores consist of eight meridional bands, lying 

 between the two poles marking the opposite extremities of the 

 body, and dividing the interpolar region into an equal number of 



