TRIBE I. AS TRIAGE A. 271 



GENUS XI. MERULINA. EHRENBERG. 



Astrceidcz tenuiter explanate aut cumulato-ramosce ; polypis parvulis, 

 discis scepius seriatim gemmantibus (sicut Meandrinis), itaque discis 

 collibusque lineatis, venose furcatis, aut reticulatis. Corolla fere solida ; 

 lamellis parvulis obliquis. 



Thin explanate or cumulato-ramose; polyps very small, disks usually 

 budding seriately (as in the Meandrince), the disks and ridges there- 

 fore linear, venosely furcate, or reticulate. Coralla nearly solid; 

 lamellae quite small, oblique. 



The Merulinse are the most graceful of foliaceous corals. The folia 

 are neatly curved and lobed, and through the ridges of the surface, they 

 often appear to have even the neuration of a leaf. Though sometimes 

 isolated, they usually grow in large clumps, consisting of leaves spread 

 out one above the other, and the whole clustered into convex or hemi- 

 spherical forms of perfect symmetry. The folia, though delicate and 

 nearly as thin as paper at the margin, are still firm, owing to the solid 

 compactness of their texture. The polyp mouths are usually confined 

 to the upper surface. The mode of budding is that of the Meandrinae : 

 the margin extends through the prolate growth of the animals and 

 opening of disk-buds, and as these new buds are formed in lines, 

 which often give off other divergent lines of buds, the ridges are linear, 

 and often furcating. But this Meandrina character passes imper- 

 ceptibly into that of the Monticularia, in which lines of buds are reti- 

 culately coalescent, so that only small radiated cones cover the surface, 

 instead of ridges. Again there is a passage on the other side into an 

 Astrueoid form, in which each cell instead of being long linear is very 

 short. The explanate or ramose form, and the oblique position of the 

 cells and of the lamellae of the ridges, are the generic characteristics. 

 The Astrsea abdita and the allied species, approach the nearest among 

 the Astraeas to this genus. The foliaceous forms pass gradually into 

 the ramose (H 77 and 79 b). 



One or two branching species of the genus so resemble the Monticu- 

 lariae in the cones of the surface, that they should fall into that genus 

 were it not for their mode of growth and very compact texture. 



The ampttata, the species for which Ehrenberg instituted the genus 

 Merulina, is one of the Agariciee of Lamarck. 



