TRIBE II CARYOPHYLLACEA. 385 



The branches are covered rather remotely with large cylindrical 

 calicles, or when alive, with prominent cylindrical polyps, each open- 

 ing at summit a flower of many rays, often of emerald green, orange 

 and scarlet tints. 



Though closely similar to the Caryophylliae, the Dendrophylliae 

 produce much stronger and more durable coralla, owing to their mode 

 of growth ; the lateral polyps in the latter add by their secretions to 

 the thickness and strength of the enlarging branch, while in the 

 former, each branch is the sole production of a single lengthen- 

 ing polyp, and is nearly filled by its axial star. Only the summit 

 of a branchlet is alive in a Caryophyllia, while in a Dendrophyllia, 

 each branch is a colony of aggregated polyps. Moreover, the striae 

 on the exterior of the calicles, when they exist, are more nume- 

 rous than the lamellae of the cell, instead of corresponding to them, 

 as in the Caryophylliae. From the Oculinse they differ widely in 

 mode of growth ; and a fragment of a branch may be distinguished 

 by the central axial star^which does not exist in that genus; moreover, 

 they form less compact coralla, the surface being either striate or sub- 

 cellular, and the interior more or less porous. They have more dis- 

 tant and much larger polyps and calicles, and more numerous lamellae 

 to the cells than the Madrepores. 



The species of Dendrophylliae grow in waters of all temperatures, 

 and to a depth of at least one hundred fathoms. 



This genus was established by Blainville, from the Caryophyllia of 

 Lamarck. Ehrenberg united it with the genus Oculina. 



A few simple species, apparently of this genus, judging from the 

 striae and lamellae, are thrown into an Appendix, as they may be 

 young of ramose forms. 



Arrangement of the Species. 



I. Arborescentiy ramose. 



*1. D. ramea. *3. D. nigrescens. 



2. D. micrantha. 



II. Sparingly ramose, or calicles simple clustered. 



4. D. aurantiaca. *6. D. diaphana. 



*5. D. coccinea. 7. D. rubeola 



97 



