26 CCELENTEKATA. 



Milleporida. Stylaster. 



MiUepora. Errina. 



Allopora. 



Stylasterida. Polypora. 



Cryptohelia. 



Distichopora. 



Subclass II. DISCOPHOBA. 



PHANEROCARPA. MEDUSAE. ACRASPEDA. 



Hydrosome consisting of a single disk, from which one or more 

 polypites are suspended. 



Free-swimming oceanic animals, whose reproduction is some- 

 times by buds, which are formed either in pouch-like organs, 

 dilatations of the stomach, or from the tentacles, or from the 

 sides of the polypite. They are the Steganophthalmata or 

 covered-eyed Medusae of Forbes ; and to them Claus has restricted 

 the old Cuvierian name of Acalephae. They are well known as 

 sea-blubbers and sea-jellies. Most of them are luminous, but they 

 do not appear to possess any special light-giving organs. 



Schmarda still (1877) includes in the Discophora the naked- 

 eyed Medusae of Forbes, which are now known to be the sexual 

 zooids or gonophores of the Gymno bias tea. 



There are three orders: but Calycozoa are sometimes ranked 

 as a subclass ; by Schmarda they are placed with the Anthozoa. 



Capable of attachment by the proximal end ... CALYCOZOA. 

 Incapable of attachment. 



Polypites numerous EHIZOSTOMEA. 



Polypite single MONOSTOMEA. 



Order I. EHIZOSTOMEA. 



Polypites numerous, modified with the genitalia into a root- 

 shaped mass. No central mouth nor marginal tentacles. 



At the extremity of the arms of the root-like mass are small 

 openings, through which the food is conveyed along a central 

 canal to the stomach. 



The embryo is a free oblong body [planula] which, soon 

 attaching itself to some foreign substance, forms a mouth and 

 stomach by invagination ; tentacles then arise from the mouth, in 



