SUBORDER ALCYONARIA. 533 



The polyps of a branch form branchlets, two to four or five lines 

 long ; and, with the spongy covering, they are an eighth of an inch 

 thick. 



The specimen here described belongs to the cabinet of Prof. C. U. 

 Shepard. 



GENUS III. TUBIPORA. 



Tubiporidce acrogence, corallis cakareis tubulatis, tubulis fasciculatis ; 

 sepimentis internis nuttis. 



Acrogenous Tubiporidse ; coralla calcareous, tubular; tubes fascicu- 

 late; no internal dissepiments. 



For an account of the structure arid growth of these polyps, see 

 H 36, 37, 69. The calcareous tubes are brittle, nearly smooth within 

 and without, though somewhat porous, and when broken across, 

 often appear to be striated, owing to the minute tubes or ducts that 

 penetrate from the interior to the exterior surface. The polyps have 

 fringed tentacles, and are from a fourth to half an inch in diameter. 

 The species differ widely in the nature and breadth of the fringe of 

 papillae, and the size of the polyp-flower ; but they are often dis- 

 tinguished with difficulty by means of their coralla. The diameter 

 of the tubes, and the frequency or regularity of the transverse septa 

 uniting them, afford almost the only characters. 



The Tubiporse have been found only in the coral-reef seas. 



Arrangement of the Species. 



*1. T. musica. 5. T. Chamissonis. 



*2. T. purpurea. 6. T. Hemprichii. 



*3. T. fimbriata. *7. T. rubeola. 

 *4. T. syringa. 



1. TUBIPORA MUSICA. 



T. coralli tubis viz '" latis, densissime confertis (in pottice 16-22), 

 paraMelis, septis creberrimis. 



15!) 



