2 PROCEEDIlSrGS OF THE NATIONAL MUSEUM vol.76 



HINDEASTRAEA COLLINENSIS, new species 



Plate 1, Figures 1, la, 2, 2a; Plate 2, Figures 2, 3, and 4 



Corralliim an irregular flattened frond broken at base, with calices 

 on all sides. Length, 103 millimeters; width, 36 millimeters at base, 

 becoming narrower higher up ; thickness, 15 millimeters. 



Corallite separated by distinct walls about 0.5 millimeter wide and 

 as much high, which inclose polygonal calices, usually five or six 

 sided. The material of the corallum is so recrystallized that it is 

 difficult to tell much concerning the structure of the wall. Judging 

 from what could be seen in some poor sections, however, and also from 

 the fact that the septa are not crowded a true theca seems to be 

 present. 



Diameter of calices about 8 millimeters, smaller on the edges of the 

 frond and near the top than on the flattened sides. Some have a 

 diameter of only 4 or 5 millimeters and others as much as 11 milli- 

 meters. Calices shallow, only 1 to 2 millimeters deep at the subcir- 

 cular fossa above the columella and less than that toward walls. 



The septa are in three complete cycles. Those of the first two 

 cycles are subequal and join the columella. The septa of the third 

 cycle bend and join those of the second just before the columella is 

 reached. All 24 septa are of about the same thickness; thicker near 

 wall where some measure as much as 1 millimeter and becoming 

 thinner toward center of calice. Septal edges depressed slightly at 

 intercorallite wall, then rise somewhat toward center to form a sub- 

 circular ridge before plunging down relatively steeply to the co- 

 lumella. The arrangement of the septa to form this ridge, to- 

 gether with what seems to be a concentration of dissepiments here, 

 gives it the appearance of an inner wall. Septa seems to be imper- 

 forate; faces with granulations which are in most places arranged in 

 vertical rows indicating probably the courses of the trabeculae ; edges 

 dentate with dentations continuous with granidar rows on faces. 



Columella spongy, made of fused ends of septa ; about 2 millimeters 

 in diameter in well-developed calices. 



Reproduction by intercalicular gemmation, mainly at the edges of 

 the corallum. 



The growth form of most of the other specimens in the suite is also 

 massive with irregular surfaces and with corallites on both sides and 

 edges. Some of these have the intercorrallite walls and the septal 

 edges v;hich adjoin them worn away, which accentuates the inner 

 raised lim of the columella fossa (see pi. 2, figs. 2, 3, and 4). Others 

 show no evidence whatever of this rim. 



Holotype and parafy pes. —Cat. Nos. 73608, 73609, U.S.N.M. 



The type specimens of HindeaHtraea discoidea White are similar 

 to this species except in growth form. The septa are the same in 



