TRIBE III. MADREPORACEA. 519 



The Seriatopores form hemispherical clumps, and are remarkable 

 for their slender graceful branches, and seriate polyps. The coralla 

 are nearly or quite solid within, owing to the obliteration of the cell 

 internally by solid calcareous secretions. The polyps resemble those 

 of the Sideropora, but are sometimes of a rose or bright-red colour. 

 The rays of the cell are scarcely distinguishable ; yet there is often a 

 distinct columella within, as in the Sideroporse ; and the upper mar- 

 gin of the cells, which is a little prominent, has a minute spinulous 

 edging. The branches are sometimes acute, and often, appear faintly 

 winged at summit, owing to a slight prominence of the interstices 

 between the adjoining series of cells. The seriate character is most 

 regular towards the summits of the branches, and is often quite lost 

 below. It is important to observe that the outer or lower branches 

 of a hemispherical clump are often quite divaricately branched, inas- 

 much as the branches have room to spread; while those of the body 

 of it are closely furcate. 



These species are confined to the coral-reef seas, and have been 

 found only in the Pacific and Indian Oceans. They graduate into the 

 Sideropores on one side, and into the slender Pocillopores on the 

 other; the latter frequently have the same solid texture, though less 

 regularly terete and not distinctly seriate in their polyps. 



The genus Seriatopora was instituted by Lamarck, for a part of the 

 old genus Madrepora ; but as it contained several unallied species, 

 it was afterwards restricted to its present limits by Blainville, who 

 assumed the Seriatopora subulata, the first of Lamarck's species, as the 

 type of the genus. 



Arrangement of the Species. 



1. S. subulata. *4. S. octoptera. 



*2. S. lineata. *5. S. caliendrum. 



*3. S. hystrix. 



1. SERIATOPORA SUBULATA. (Lamarck.) 



S. ramis validiorilus (2'", et basi totidem 4'"), raro coalitis ; polypis 

 <i-6-seriatis, virentibus. Corallum ramulis subulatis, superne ramn- 

 loso-verrucosis, apice tetrapteris aut hexapteris. 



In very ramose hemispherical clumps, branches quite stout (2 lines 



