362 CATALOGUE OF PORITES AND SYNARiEA. 



This species consists of small, irregular, rapidly dividinu' brauclies, 

 forming- more or less dense clumps, generallj^ of small size, but attain- 

 ing a sx)read of at least 28*^'" and a height of at least 18'^"\ When most 

 perfect these clumps often have a comparatively regular, strongly con- 

 vex or hemispherical shape, with the branchlets much crowded or more 

 or less widely separated at triie surface ; but the majority of specimens 

 are unsymmetrical in form. The branches and branchlets are cylin- 

 drical or more or less comi)ressed, and generally very irregular in shape 

 and in the extent to which they subdivide ; they usually ramify in all 

 directions, but sometimes the tendency is toward vertical growth mainly. 

 The clum])S generally start from a single stem below, and in the lower 

 part are more or less open, but in occasional specimens the basal portion 

 becomes nearly solid or may even be incrusting. Such specimens prob- 

 ably grew at the surface of the water and generally have very short, 

 stout and irregular branches. Although the branches in any form 

 rarely exceed 12 or 13""" in diameter, the basal stem is sometimes much 

 larger, and in one instance measures 40'"'". The ends of the branchlets 

 at the surface of the clumps are often much enlarged (while in process 

 of division) and very irregularly furcate or lobed, with sometimes as 

 many as a dozen short protuberances. The branches very rarely 

 coalesce either in this species or in clavaria. Nearly all the specimens 

 from any one locality have nuich the same general appearance. 



The Dry Tortvgas (PI. XV, figs. 1 and 2). — Most of the specimens in the 

 collection came from two localities, viz., the Tortugas and Key West. 

 The Tortugas series contains one hundred and twenty specimens, includ- 

 ing the largest and finest obtained. They are, as a rule, more symmetrical 

 than the specimens from Key West, generally with rather stouter and 

 more regular branches, which measure from G to 13"'"' in diameter. The 

 branching is much less rapid below than above, but toward tlje toj) it is 

 very frequent, forming at each point of division from two to six branch- 

 lets, some of which generally divide very soon again. These branchlets 

 niaj' diverge irregularly in several directions or tend to grow in a single 

 l)lane, giving rise to a wide fan-shaped figure, the basal portion of which 

 is very broad and flattened. From the frequency of branching toward 

 the top, the ends of most of the terminal branchlets are more or less 

 enlarged or furcate, produtyng the generally denser structure at the 

 surface. The character of the growth is more or less determined by the 

 nature of the surroundings, and while most specimens attain at least a 

 moderate height, some, probably growing at the surface, are very low, 

 spreading mainly from the margins. The branches and branchlets vary 

 in shape from cylindrical to much compressed and are more or less bent 

 and twisted. Where not killed by the filling in of sand or the growth 

 of nuUipores and other incrusting forms, even large specimens may be 

 alive for nearly their entire height ; in one case the height of the living 

 portion is 18*^'". The cells range in size from 1 to 2""", are usually moder- 

 ately excavated and not as irregular as in the Key West specimens* 



