4 ANTHOZOA. 



The Anthozoa are divisible into the following Orders: 



I. — Hydroida. Polypes compound, rarely single and naked, the mouth encircled 

 with roughish filiform tentacula ; stomach without proper parietes ; intestine ; 

 anus ; reproductive gemmules pullulating from the body and naked, or contained 

 in external vesicles. — PoJypidoms homy, fistular, more or less phytoidal, external. 



II. — AsTEROiDA. Polypes compound, the mouth encircled with 8 fringed tentacula ; 

 stomach membranous, with dependent intestinal appendages ; intestine ; 

 anus ; ovules produced interiorly. — Polypc-inass variable in form, free or per- 

 manently attached, carnose, generally strengthened with a homy or calcareous 

 axis enveloped with the gelatinous or creto-gelatinous crast in which the polypes are 

 immersed, and which open on the surface in a starred fashion with 8 rays. 



III. — Helianthoida. Polypes single, free or permanently attached, fleshy, naked 

 or encrasted with a calcareous polypidom, the upper surface of which is crossed 

 with radiating lamellae ; mouth encircled with tubulous tentacula ; stomach mem- 

 branous, plaited ; intestine ; anus ; oviparous, the ovaries intemal. 



