434 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



PIRONASTRAEA ANTIGUENSIS, new species. 



Plate 112, figs. 2, 2a; plate 113, figs. 1, la. 



Corallum massive. Type a small specimen, 48 mm. long, 32 mm. 

 wide, and about 30 mm. thick. Subsequently two larger specimens, 

 apparently referable to this species, will be described. 



Width of calicinal series, measured between colline summits 5.5 

 mm. to 7.5 mm. Valleys shallow, about 1.5 mm. deep. Collines 

 with broader bases than in P. anguillensis, some colline-profiles are 

 more triangular than in the latter species. Distance between cali- 

 cinal centers in the same series about 4.5 mm. 



Septa numerous, about 48 in a calice 6 mm. in diameter, between 

 12 and 14 extend to the axis, other septa shorter, irregularly fused 

 in pairs or in groups of three. Around the calicular edges all septa 

 are ^ubequal; their thickness about the same as or slightly less than 

 the width of the interseptal loculi. The septal margins with bluntish, 

 crowded dentations, 20 were counted in a length of 3.4 mm. 



Septo-costae subequal, crowded, each of three counts in different 

 places gave 22 to 5 mm. of linear distance. Synapticulae numerous, 

 crowded, 9 were counted in a distance of 2.5 mm. along the course 

 of a septum. 



Columella false, papillary, not sunken in a definite pit. 



Locality and occurrence. — Antigua. Type (pi. 112, figs. 2, 2a) from 

 the Antigua formation, station 6854, Rifle Butts, T. W. Vaughan 

 collector; and station 6880, west side of Otto's estate, T. W. Vaughan 

 collector. The last-mentioned specimen is silicified and broken, but 

 as it presents the general aspect of the type of P. antiguensis, and has 

 from 18 to 22 septo-costae to 5 mm., the specific identity of the two 

 specimens appears certain. 



Cuba, station 7514, about 5 miles nearly due east of monument 

 H 4 on the east boundary of the United States Naval Reservation, 

 Guantanamo, altitude about 400 feet a. t., collected by O. E. Mein- 

 zer. The latter specimen is represented by plate 113, figures 1, la. 



Type.— No. 325177, U.S.N.M. 



Paratype.—No. 325179, U.S.N.M. 



P. antiguensis differs from P. anguillensis in its more massive 

 growth form, wider valleys, lower collines, more numerous septo- 

 costae, and the absence of a columella pit. The calicinal centers in 

 the specimen from station 7514, near Guantanamo, Cuba, are usually 

 joined by an axial septum extending from one to the next center, 

 producing the appearance of an axial lamella. The lamella, how- 

 ever, is not a columella, for the calicinal centers are usually recogniz- 

 able, and when they are distinct there are a few' papillae in the 

 columellar area. It appears that the well-developed axial lamella is 

 one of the specific characters, but the suite of specimens, three in all, 

 is too small to be sure of this. 



