INVERTEBKATE ANIMALS. 7 



AcTiNozoA, till the researches of Mr. Moseley, in the 

 " Challenger," proved them to be true Hydrozoa. 



H Examples of Sti/laster, Allopora, and Disticho- 

 pora, from the Pacific. These have hitherto 

 been brought to this country in fragments : 

 to obtain them in anything like an entire 

 state it is probably necessary to employ a 

 diver to detach portions of the rock on which 

 they grow. 



Class ACTINOZOA. uxriv, a ray; i^wov, an 



animal. Internal cavity compound. 



The groups in this class are named and arranged chiefiij after Milne 

 Edwards' Histoire Naturelle des Coialliaires ; but most valuable 

 aid has been received from the magnificent ivork by James Dana, 

 on the Zoophytes of the United States Exploring Expedition, 

 1838-42. 



Group 18. — Order KUGOSA. rugosus, wrinkled. 



The members of this order are, with rare exceptions, 

 only known as Palaeozoic fossils. The rays 

 are in multiples of four. 

 ^ Polished sections, chiefly from Devonian rocks. 

 The Order Rugosa includes 224 species. 



Order ZOANTHARIA. ^wov, an animal; av^oc, 

 a Jloicer. Parts in multiples of 5 or 6. 



Sub-order SCLERODERMATA. a-xXripos, hard; 

 UpiKu, the skin. Corallum secreted within the 

 animal. 



Group 19.— Genera SERIATOPORA (Lamarck), and 

 POCILLOPORA (Blainville). The former from 

 series, a row ; the latter from imcillum, a little cup. 

 Estimated number of species : recent, 28 ; British, ; 



