134 . 
Near the sponges begin the Coelenterata, This branch 
includes the hydroids, the various forms of jelly-fishes, the sea- 
anemones and the corals. 
The hydroids and jelly-fishes are represented by a number of 
glass models. These include one of the Portuguese man-of-war. 
Closely related to the hydroids are the species of the genus 
Millepora. They form solid coral-like masses. 
The remainder of Case i is occupied by the Actinozoa. A few 
of these, the sea-anemones, form no solid skeleton and are able to 
move slowly about. These soft, very contractile animals are 
represented here principally by glass models. 
Of the corals which form a solid limestone skeleton there are 
two orders, viz.: the Zoantharia and the Alcyonoida, All the 
solid corals shown in Case i and the north half of Case 2 belong 
to the first named order. The {Fungia) mushroom corals are sim- 
plest in structure. The individuals are nearly circular and may 
be several inches in diameter. Each is the skeleton of a single 
animal. Usually, however, the coral mass is composed of the 
coalesced skeletons of many coral animals. These individual 
animals may be of considerable size and distinct from one another, 
as in Astrcea ; or they may coalesce with their neighbors and be 
of considerable size, as in the brain-coral (Meandrina), or small. 
In the stag-horn corals {Madrepora) the individuals which secreted 
the coral are quite small. 
The second order of corals, the Alcyonoida^ shown in the south 
half of Case 2 , includes the sea fans, the sea-whips, organ-pipe 
corah etc. There is not often a limestone skeleton, although this 
is occasionally present, as in the precious red-coral. Usually the 
supporting skeleton contains a horny axis. This may be observed 
in many of the specimens. There are several alcoholic prepara- 
tions of corals and some glass models, which show the organiza- 
tion of these interesting animals. 
