TRIBE III. MADREPORACEA. 549 



Mi/lcpora platijphylla, Ehrenberg, Ixxiv., lobis erectis, varie plicatis costatisque 



No. 3. subreticulatis.cristisacutis, continuis, sub- 



The M. porulosa of Ehrenberg, may be, as lobatis, stellulis [cellis] creberrimis, ab 



he suggests, a variety of the above. It is interstitiorum poris ncn distinctis, prope 



described as follows: " Pedal is, effusa, basin minus frequentibus inaequalibus,me- 



efflorescens, foliacea, compressa, levis, dio majore poro [cella] minoribus cincto." 



FAMILY III. PORITID^. 



Madreporacea polypis creberrimis, basi omnino pwost coralligenis, et 

 superne non coralligenis itaque polypis expansis scepius eminentibus, 

 coralli caliculis nullis, cellis contiguis, paulum profundis aut super- 

 ficialibus, infra vix dispiciendis. 



Polyps closely crowded, forming continuous porous coral secretions 

 in their lower portions, and not coralligenous towards the summits, 

 when expanded, therefore, prominent above the surface, and the 

 coralla without calicles, with the cells shallow or superficial and 

 scarcely traceable through the interior of the corallum. 



The animals of the Poritidse, when expanded, often stand like pedi- 

 cellate flowers over the surface of the zoophyte, and are of various 

 shades of green, red, brown, and lilac. The coralla are equally porous 

 throughout, with scarcely a trace of the cells distinguishable in the 

 interior. The shallow cells of the surface are sometimes wanting 

 entirely, excepting a point to mark their position ; they are usually 

 granulous over the interior and bottom ; but there is, in most species, 

 a stellate arrangement of the echinulate granules. This family in- 

 cludes the two genera Porites and Goniopora; the former with but 

 twelve tentacles, and the polyps hardly a line in diameter; the latter 

 with larger polyps and more than twelve tentacles. In the texture of 

 the coralla, the irregularly radiate character of the shallow contiguous 

 cells, and the frequently salient polyps, they are closely alike. (See 

 note, page 407.) 



138 



