278 ZOOPHYTES. 



on the Merulinse. The latter resemble somewhat the Oculinae, but 

 the summit of a branch is prolonged by the prolate mode of marginal 

 growth, and the polyp appears some distance short of the apex ; 

 whereas in the Oculinse the bud forms the extremity of the branch, 

 and is immediately connected with one preceding. 



The polyps in the species examined when alive, appeared to have 

 no tentacles, except the prominences over the spines of the calicles. 

 The calicles have a broad shallow cell arid contain six to twenty 

 lamellae, more or less raggedly dentate or denticulate, which extend 

 to the centre and are separated by deep cellules. The exterior animal 

 tissue often dries over the cell, and reduces its aperture to one-third 

 its actual diameter. 



The Echinoporse are but a step removed from the Merulinae, bear- 

 ing the same relation to them as the Orbicellae to the other Astraeae. 

 Occasionally we observe a cell subdividing from the opening of a 

 disk-bud. 



The Echinoporee are confined to the coral-reef seas. 



This genus was instituted by Lamarck for a single species brought 

 by Peron and Lesueur from New Holland, and was named in allu- 

 sion to the echinate surface of the corallum. Blainville unites it 

 with some of Lamarck's Explanarise, and names the genus Echinas- 

 trcea. Ehreriberg suggests their arrangement along with the Madre- 

 poridae, from which they are quite distinct, and appears to have 

 placed one species in his genus Expkmaria. 



Arrangement of the Species. 



. I. Foliaceous, bifacial. 

 *1. E. undulata. 



II. Foliaceous unifacial. 



2. E. rosularia. *4. E. reflexa. 



3. E. ringens. *5. E. aspera. 



III. Ramose. 



*6. E. horrida. 



1. ECHINOPORA UNDULATA. (Dana.} 



E.foliacea; erecta, bifrons, undulata. Cwallum tenue, utraque super- 

 faie leviter striatum et spinuloso-asperum ; cettis sparsis vix tumidis, 

 68-radiatis. 



