DISTKIBUTION OF GROWTH-FOKMS. 135 



P. Guadalupe 5 (PI. XVI. fig. 6). The lobes are short and thick, but there is some 



irregularity in the distances between the forkings, and the stock rises chiefly in 



height. 

 P. West Indies x. 10 (PI. XIV. fig. 3). This is a small rounded tuft, apparently 



complete, but perhaps distorted by Balanids. 

 P. West Indies x. 22 (PI. XVI. fig. 5). This also forms an irregular tuft of short, 



thick, irregularly forking lobes. 

 P. West Indies x. 23 (PI. XV. fig. 3). The forking is like the irregular dividing of 



the lobes of a ridge. 

 Porites x. 6 (PI. XVI, fig. 2). A rather more open tuft (placed here provisionally 



as possibly a West Indian form). 



c. Stock rises as a single stout stem which branches more freely. 



i. With more or less pronounced tapering of the stocks upwards. 



P. Antigua 2 (PI. X. fig. 4). With dichotomous forking at open angles, prongs 



straight and tapering. 

 P. Bermuda 2 (PI. XII. fig. 3). Short thick stems with thick but tapering prongs. 

 P. Bermuda 3 „ „ „ 



P. West Indies x. 17 (PI. XVI. fig. 3). With thinner and longer prongs. 

 P. West Indies x. 21 (PI. XV. fig. 4). Young form, very short and squat, rapidly 

 tapering to small mammiUate prongs. 



ii. With no regular tapering or thinning down, but on the contrary, prongs may be 

 irregularly swollen into knobs, or flattened, without, however, any increase in the average 

 thickness of the stems and branches. 



a. The branches and prongs all tending to bend in toward the axis. 



P. Antigua 1 (PI. X. fig. 1). The original single stem of the overturned stock is seen 



on the right hand side of the picture, see for description, text, p. 46. The stems 



show irregularities in thickness and in the forms of the prongs, some swollen, 



some pointed. The branchlets of the overturned stock have bent up somewhat 



towards the light. 

 P. Gura^oa 3 (PI. IX. fig. 6). A small tuft with branchlets swollen, and the st«ms 



bending upwards towards the light. 

 P. St. Thomas "2 (PL XI. fig. 1). The stems are thick, crowded, regular forkings at 



wide angles, and at short distances. 

 P. Porto Rico 1 (PI. XI. fig. 3). The stems are thin, long, sweUing irregularly, and 



with strong tendency to bend inwards. 

 P. Florida 2. See text, p. 72. 

 P. West Indies x. 2 (PI. XIII. fig. 1). The stems are thick, and fork very freely, but 



at comparatively short distances, so as to produce a tangle. Branchlets often 



long, thick, and fusiform. 

 P. West Indies x. 3 (PI. XII. fig. 1). The stems are long and tend to curve inwards 



towards the axis. Forking at quite irregular distances, sometimes far apart, 



resulting in long, stout, finger-shaped branchlets, at others so close as almost to 



suggest that the branchlet divided into more than two. 

 P. West Indies x. I4 (PI. XIII. fig. 3). On this interesting young form, see 



text, p. 90. 



