88 PKOOEEDINGS OF THE NATIONAL MUSEUM vol.83 



becoming more or less filled up below and appearing lamellar in 

 longitudinal section as the trabeculae lose their individuality. The 

 septa of the first two cycles are much thicker and more prominent 

 than the rest. The columella is well developed, spongy, and papil- 

 lose on the surface. The dissepiments are absent, but there is a 

 great development of the synapticulae. 



Measurements. — Corallum measures: Height, 51 mm; diameter 

 near base, 15 mm ; maximum diameter between base and upper sur- 

 face, 32 mm. 



Holotype.—V.S.'^M. no. 74483. 



Occwrrence. — Upper Cretaceous limestone in the railway cut be- 

 tween Cambridge and Catadupa, Jamaica (Trechmann collection). 



Retnarks. — The calicular surface of this species closely resembles 

 the typical Anabaciids, but the change in the structure of the septa 

 from trabeculate-fenestrate to more or less laminar is very pro- 

 nounced, resembling the structure found in Astraraea Felix, but the 

 wall of the corallum in this genus is golid, imperforate, and costate 

 (as it is in Trochoseris Milne Edwards and Haime) ; at least this is 

 true of specimens labeled Astraraea media in the National Museum 

 in a collection of the Gosau corals from Prof. Felix. Synastrea 

 agaridtes (Goldfuss), type of the genus, also from the Gosau beds, 

 specimens of which are in the National Museum, agrees more nearly 

 with adklnsi from the standpoint of structure and character of the 

 exterior, although the filling up of the lower parts of the septa is not 

 so pronounced. The distinct calices of this species also distinguish 

 it from other species of Synastrea.^ most of which have shallow calices 

 not bounded by a distinct groove, as in Thamnnsteria Lesauvage. 



Family OULASTREIDAE Vaughan 



PRODIPLOASTREA, new genus 



Generic diagnosis. — Corallum massive, astreiform, forming a 

 rounded pedunculate mass. Corallites cylindrical, of medium size, 

 projecting slightly above the common surface, united by confluent 

 septo-costae and a thin, well-developed exotheca. Septa not numer- 

 ous, thin, little exsert, not uniting, continuous with the septo-costae, 

 laminar in structure, very little perforate, and lightly dentate on 

 the upper edges. Corallite wall porous, synapticular in origin. 

 Synapticulae poorly developed except in the thecal ring. Endotheca 

 scanty. Columella absent or very rudimentary. No pali. 



Genotype. — Prodi ploastrea schindewolf, new species, from the 

 Upj)er Cretaceous of Jamaica. 



