50 CORALS AND CORAL ISLANDS. 



true polyps ; and Professor Verrill remarks on the resemblance 

 of the tentacles to those of the Oculinae. The stellate 

 character of the calicle also proves that the animals must be 

 polyps. 



Madrepore tribe, or Madreporacea. — In this tribe tlie 

 coralla, even to the walls of the corallets, are remarkable for 

 being porous, and the radiating lamellae of the polyp-cells 

 are narrow, often perforated or imperfectly developed, and 

 frequently mere points. The coralla are either branched, mas- 

 sive, or foUaceous. Budding is lateral, and in the branching 

 species there is either a parent polyp, as in Madrepora and 

 Dendrophyllia, or a terminal budding cluster. This peculi- 

 arity has been already illustrated in the figure of Madrepora 

 aspera, on page 29. On the following page there is an outline 

 sketch of another species, the Madrepora formosa D., common 

 in the Feejees, and also in the East Indies. The two species 

 here mentioned give a good idea of the ordinary character of 

 the Madrepore corals. One of the polyps of the Madrepora 

 cribripora D., a species collected in the Feejees, is represented 

 much enlarged in the accompanying figure. The natural size 

 of the expanded polyp in this genus is generally from an 



POLYP OF M. CKIDKIPOKA, D. 



eighth to a twelfth of an inch across the star. The disk of 

 the polyp is quite small, and the number of tentacles is always 

 twelve. The most common colour of the polyps is green, 

 while that of the general surface between is ordinarily a pale 

 or a dark umber. In many species of Madrepora the branches 

 spread out laterally from a central or lateral trunk, and coalesce 

 together into a complete net-work, having the form of a shallow 

 vase ; and the interior of the vase is filled with multitudes of 

 short, . cylindrical coral stems, rising from the reticulating 



