98 GUIDE TO THE AUSTRALIAN MUSEUM. 



3. Spatangidea. — In this order the body is more or less 

 irregularly heart-shaped, both mouth and posterior open- 

 ino- on the lower side eccentric, the teeth absent, and the 

 ambulacral areas petaloid, often only four-leaved. Echi- 

 noneus ci/closiomus, Maretia j^^ci'^^ulata, Breynia austra- 

 lasficB, Ecldnocardium australe, Remiaste?' wpicatus^ and 

 Schizaster ventricosus are good examples. 



Sub-Class v.— The HOLOTHUROIDEA, or Sea 



Cucumbers, Bech-de-mer, Trepang, &c. — In this sub-class the body 

 is elongated, with a thick leather-like skin, which contains 

 numerous calcareous spicules resembling wheels, anchors, latticed 

 plates, hooks, &c. ; the mouth is surrounded by a series of con- 

 tractile tentacles, which are often branched and plume-like. There 

 are two orders in this sub-class : — (See Case 17.) 



1. Pedata, with usually five rows of ambulacral feet. 

 Examples — Holothuria vagabunda, Colochirus australis, 

 Thyone okeni, Thyone s2nnosus, and Phylloijliorus 'pers'pi- 

 cillum. 



Apoda, without ambulacral feet. Examples — Chirodota 

 japonica, C. australina, and SynaiHa dolohrifera. 



o 



Sub Kingdom V.— COELENTERATA. 



In this group are included the Sponges, Jelly-fishes, Sea- 

 Anemones, Corals, and Hydroid Zoophytes. These all possess a 

 central body cavity, which serves alike for circulation and 

 digestion ; they are radially symmetrical, and are composed of 

 many cells. There are three divisions of this sub-kingdom — the 

 Hydrozoa, or Jelly-fishes and Zoophytes ; the Actinozoa, or 

 Corals ; and the Po.iifera or Sponges."^ 



Division I— HYDROZOA. 



Contains Polyps with a simple gastric cavity in which the mesen- 

 teric lamellae are altogether absent, or only exist in a very 

 rudimentary condition. The sexual generation assumes the form 

 eitlier of free-swimming MedusEe, or of rudimentary medusoid 

 buds, which are not separated from the parent body. Colonies 

 of Hydrozoa usually consist of tree-like stocks. 



* 8ee Lendenfeld's CatalogTie of Sponges, No. 13 Museum series. 



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