84 VERRILL, SYNOPSIS OF 



ter .02 to .07, average about .06; diameter of largest 

 cells about .015. 



Loo Choo Islands. Rev. S. W. Williams. 



This s^jecies is allied to M.formosa Dana; M. hracM- 

 ata Dana; M. laxa Lam.; and M. gracilis Edw. and 

 Haime, but differs from all in having much smaller cells, 

 as well as in its mode of branching. The first has lon- 

 ger, more slender and acute, and scarcely proliferous 

 branches, with much longer and more slender corallites, 

 which are more nearly equal and not crowded nor thick- 

 ened, with much larger cells. The surface is more 

 porous and more coarsely granulous. M. brachiata has 

 much stouter and less subdivided branches, with much 

 longer corallites, which are crowded, less unequal, and 

 obliquely truncated at summit, with oval and large cells. 

 M. laxa differs in its mode of branching and larger ver- 

 rucee and cells. M. gracilis has nariform corallites. 



M. arbiiscula resembles it somewhat in mode of branch- 

 ing, but has stouter branches and much larger cells and 

 corallites, and its surface is coarsely porous and scabrous, 

 costate on the corallites. 



MoNTiPORA EXESA VerHll, sp. uov. 



Montipora foliosa? (Vol. V, p. 25), non Edw. and Haime. 



Since describing this coral I have been able to exam- 

 ine a large and fine specimen of M. foliosa and must 

 regard it as a distinct, though allied, species. 



This resembles it in the character of the lower surface, 

 and probably, also, in its mode of growth, but differs in 

 having on the upper side much coaser, thicker, and 

 round-topped papillce, most of which are united more or 

 less into groups, crests, and long ridges, which are united 

 by thin cross ridges, so as to form very unequal and irreg- 

 ular deep pits over the whole surface, which give it a 

 rough, eroded and excavated appearance. The cells are 

 inconspicuous, very small (scarcely .02 inch), and situ- 

 ated at the bottom of the pits and often among isolated 

 papillse. They have six larger septa alternating with six 

 very rudimentary ones. The external surface is very 



