TRIBE III. MADREPORACEA. 523 



Seriatopora caliendrum, Ehrenberg, G. Ixxiii., sp. 4. 



The S. valida of Ehrenberg is described from a specimen in the Berlin Museum, as fol- 

 lows : " Ramulis arete complexis et ssepe in laminas compressas coalitis reticulatisque, 

 ramulis flexuosis, conniventibus, apice acutis, hexapteris, stellulis subciliatis, non promiuulis, 

 scabritie tenui." " Habitus caliendri, sed ramuli paulo crassiores, magis conniventes et 

 coalescentes. An specie diversa ?" A variety of the octoptera ? 



GENUS IV. POCILLOPORA. LAMARCK. 



Favositida furcato-ramosce ; polypis breviter tentaculatis, tentaculis 

 cequalibus; secretionibus corallicis interstitiorum fere solidis ; ramis 

 nunquam teretibus, scepe verrucosis. Corolla cellis contiguis et apice 

 angulatis, lamellis angustissimis sapius vix conspicuis. 



Furcato-ramose ; polyps with short equal tentacles; coral secretions 

 of the interstices nearly solid ; branches never terete, often verru- 

 cose. Coralla with the cells contiguous, and at apex angular, the 

 lamella very narrow, and generally rather indistinct. 



The cespitose clumps are generally hemispherical, as in the pre- 

 ceding genus, and often very neatly so ; the size of the branches, and 

 the intervals between, being quite regular. The polyps are like those 

 of the Madreporse. The coral secretions are very firm and solid, yet, 

 on making a section by fracture, the cells, excepting in a few slender 

 species, may be traced to the centre, arid exhibit the transverse septa 

 very regularly arranged. At the summits of the branches, the cells 

 are contiguous and polygonal, with very thin interstices ; but, below, 

 they are a little more separated, though the intervals seldom exceed 

 their diameters. 



These cells are never over half a line in breadth. The lamellae are 

 generally very narrow or indistinct, except two opposite, in some 

 species, which are enlarged so as to meet and form a partition across 

 the cell, with a columella at centre ; and in others of the Pocilloporae, 

 only one of these two lamellte is distinguishable, extending from the 

 side and terminating in the columella. 



The branches are commonly somewhat flattened, occasionally three 

 to four inches wide; and in all, except the more slender species, they 

 are thickly covered with small prominences or verruca, consisting of 



