HALL 24, 
SPONGES, JELLY-FISHES, CORALS, ETC. 
In this hall are exhibited the materials illustrating the branches 
of the animal kingdom known as the Pj'otozoa , the Porifera , the 
Coelenterata , and the Echmodermata. 
Cases 1 and 2.— The Protozoa, almost wholly animals of 
microscopic size, are illustrated by models, faithful representa- 
tions of these animals magnified 2,300 times. These are found in 
the extreme south end of the case. 
The Porifera, or sponges, include some interesting forms, such 
as Neptune’s cup, the glass-rope sponge, Venus’ flower basket, etc. 
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 1 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 1 belong to the first-named order, as 
well as many of those in Case 2. The simplest of these corals in 
structure are the species of the genus Fungia. The individ- 
uals 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. 
