A. E. Verrill — Corals of the Genus Acropora. 227 



It has slender, acute, elongated, proliferous branches, with rather 

 small axial corallites, about 3 mm in diameter and 1 or 2 mm exsert, with 

 porous walls and a small, 12-rayed calicle. 



The radial corallites are loosely, irregularly arranged, and very 

 unequal in length. On the distal 25— 40 mm there are many, longer, 

 ascending, tubular corallites, somewhat incurved, not appressed, with 

 the aperture oblique. The larger of these, which are free distally 

 and bear one to several small basal buds, may be 6 to 8 mm long and 

 1.75-2 mm in diameter ; some of them give rise to small ascending- 

 proliferous branches. 



Between these are other tubular and tubo-nariform radial calicles 

 that are about as large, but not so long, attached for nearly the 

 whole length, but not appressed, or only slightly so, with the aper- 

 ture oblique, round or slightly elliptical, and directed upward, and 

 without a free inner lip. Part of these are somewhat compressed, 

 with the outer wall thickened and convex ; others are nearly round 

 and straight, but all have the outer lip thickened, prominent, obtuse, 

 sometimes slightly incurved, sometimes straight. 



The corallites are about 3-5 mm long and 1.75 mm in diameter. 

 Others mixed with these are one-half shorter, with the aperture 

 less oblique. The wall of the distal corallites is echino-costulate ; 

 that of the more proximal ones is densely echino-granulate, usually 

 with the granules in series. 



On the proximal half of the branches many of the corallites are 

 immersed or have only short appressed lips ; on the larger branches 

 they are nearly all immersed, with small stellate calicles. 



The radial calicles all have about 12 narrow, unequal septa, the 

 directives a little wider. The ccenenchyma is uneven, pitted, and 

 roughly granulated. 



This species is related to M. alliomorpha and M. assimilis Brook, 

 =M. appressa Dana, but seems to be distinguishable on account of 

 its much longer and very unequal radial corallites, which are not 

 so much appressed. 



In the length of the radial corallites it is more like the typical 

 appressa of Ehr., but that is said to have the corallites strongly 

 appressed and not striate. 



As it cannot properly be referred to A. rosacea (Esper), I propose 

 to give it, for the present at least, a new name (A. dissimilis). 

 Future comparisons with the types may lead to the union of this 

 and several of the allied forms. The union of this and appressa 

 (Dana) was suggested by me in 1864, but at present the tendency 



