WEST INDIAN ISLANDS PORITES. 51 



there thinning away to narrow single bands, but where the calicles are best developed they are 

 stout. The top surface of the walls may be composed of flakes, either smooth or else with 

 irregular faintly frosted granules and threads, coarse and thick, scattered upon them. The septa 

 are irregular projections from the edges of the bands or flakes ; they are broad and their 

 usually widened ends are slightly echinulate ; the interseptal loculi are cut back to varying 

 depths into the flakes irregularly or smooth and rounded. The pali are usually close, 

 irregular rings of 5 large frosted granules, one at times very large, and here and there joined 

 to the tip.s of septa. They do not rise high in the calicle and mostly surround a minute, open 

 fossa, but the calicle is nowhere deep, being early filled up with skeletal reticulum. 



The section shows a close axial network of fine skeletal matter, surrounded by a very 

 dense, almost solid layer. 



This coral cannot well be brought into line with the great mass of the branching West 

 Indian forms, inasmuch as its forking seems to be very irregular. It is, however, obvious that 

 when forking takes place very rapidly, say at distances less than 1 cm. apart, great irregu- 

 larities would be expected owing to the excessive crowding which would result. 



It is interesting to note that this small branching form shows a similar flaky reticulum 

 with round pores as does the only explanate form known from this locality (No. 3). We call 

 attention to this fact, although we can make no use of it. There is no trace of it in the blue 

 coral from this locality, so that it is not a character common to all the Barbuda Porites. 



a. Zool. Dept. 99. 6. 26. 9. 



33. Porites Barbuda 3. (P. Barbuda: tertia.) (PL III. fig. 1 ; PI. XVII. fig. 5.) 

 [Barbuda, coll. Gregory ; British Museum.] 



Description. — The corallum is explanate, with edges drooping and even bending under. 

 The surface is irregular, having somewhat smooth facets separated by bluntly angular ridges. 

 The colony loosely encrusts dead corals. 



The calicles are small, 1 mm. and under, cii'cular and shallow, but somewhat sharply 

 sunk as if punctured into the surface. The walls are generally thick and consist apparently 

 entu'ely of continuous flat layers of smooth, horizontal, flaky skeletal elements perforated with 

 small cii'cular holes. No traces of trabecular elements appear at all. The septa are pro- 

 jections from the edges of these horizontal layers, sometimes short and thin or somewhat 

 longer and knobbed. Neat rings of deep, round, interseptal loculi, surround a large columellar 

 floor to the calicle. This is sometimes soKd, at others rises into an irregular reticulum which 

 unites with that of the wall, so that the only trace of radial symmetry is seen in the circular 

 rings of small, round, interseptal loculi. Parts of the surface become in this way continuously 

 but raggedly reticular, with only irregular breaks representing the caUcles. 



This coral should be compared with P. AnguiUa ■;!. The two appear somewhat alike, and 



H 2 



