88 VERRILL, SYNOPSIS OP 



The lower surface is destitute of papillifrtrm processes, 

 and nearly even, composed of a very porous spongiforra 

 tissue, roughened with minute sharp points. The cells 

 are very small (.01 inch), regular, wholly immersed, sur- 

 rounded by a circle of small spinules, thickly scattered 

 over the surface, except towards the edge where they 

 are generally more distant and often larger, usually with 

 twelve very small, rudimentary septa. Upper surface 

 very porous, somewhat undulated, a little uneven, thickly 

 covered with small, unequal, prominent, round-topped 

 papillae, which have a very open spongifonn texture, their 

 surface covered with rough projections. Sometimes these 

 papillae are less developed and appear like small rounded 

 clusters of spongy trabiculse, which project all over the 

 surface and are lacerately divided. Cells thickly scat- 

 tered over the surface, each usually surrounded by a clus- 

 ter of four or five of the larger papillae, considerably 

 larger than those of the lower side (about .03 of an 

 inch), with six quite distinct septa, which extend about 

 one-fourth across the cells. Towards the central parts 

 of the coral the cells are generally somewhat larger and 

 have twelve septa, six very narrow ones of the second 

 cycle alternating with the six larger primary ones. 



Close to the edge the papillae sometimes form radiating 

 rows, or unite into short, thin ridges. The largest pa- 

 pillae are scarcely .02 of an inch in diameter, and about 

 .04 in height. 



Hawaiian Islands. Museum of Yale College. Numer- 

 ous specimens are also in the Museum of Comparative 

 Zoology, which were collected by Mr. A. Garret. 



This species appears to grow in broad horizontal fronds, 

 having an undulated surface, and attached or encrusting 

 in the central parts, the edges becoming free. In the 

 character of the upper surface it resembles somewhat M. 

 grandifolia Dana, and M. expansa Dana, but has a much 

 more porous texture and thicker and rounder papillae, 

 but both the latter species have a very different lower 

 surface, with prominent cells, which are three or four 

 times broader, and their fronds are thinner and firmer. 

 The even, nearly smooth lower surface, with minute punc- 



