VAUGHAN : MADREPORARIA. 



65 



Pocillopora diomedeae, sp. nov. 



Plate 2, figs. 2, 2a; plate 6, fig. 1. 



Corallum composed of short, subterete or compressed elliptical, or wide, flattened 

 blunt branches, the ends sometimes incrassate or subclavate. Seven broken 

 branches were obtained, probably all belonging to the same colony, and because of 

 the darker, reddish color of the lower ends the total length is probably represented. 



* The specimen figured. 



Verrucae obsolete or irregular in development. They may bear from three 

 to five calices, scarcely elevated above the usual level of the surface of the 

 branch, or may be as much as 3.5 mm. tall and covered by as many as 20 calices. 

 The larger verrucae are appressed, greater diameter 6 mm., lesser, 3.5, with the 

 apices distally directed. They are better developed along the more compressed 

 edges than on the flatter sides. Their distance apart is too variable to possess any 

 systematic value. 



Calices with slightly elevated margins; deep over the whole surface, about 1 

 mm. near the lower end. The apical ones are separated by narrow, acute walls 

 and have a maximum diameter of 1.5 mm.; those on the sides, about 30 mm. 

 below the apex, are 1 mm. in diameter and are separated by walls from .5 to .75 

 ram. thick; those near the base (65 mm. frora the apex), are about .75 mm. in 

 diameter and are separated by an equivalent thickness of coenenchyma. Tlie 

 calices on the verrucae are about 1 mm. in diameter and are closer together than 

 on the adjacent portions of the side of the corallum. 



Septa are indistinct in the apical calices, distinct in practically all others, but 

 somewhat irregular in development, usually best developed near the lower end of 

 the branch. The number is twelve, two complete cycles, with occasional members 

 of the third. A varying number, from one to six, are much thickened and have 

 very exsert edges ; but all, excepting one or both of the directives, are narrow, 

 rendering the fusion to the columella invisible from above. The inner margins 

 are spinulose- The columella is usually well developed, arises deep down in the 



