480 BULLETIN 103, "UNITED STATES NATIONAL MUSEUM. 



ACROPORA PANAMENSIS, new species. 



Plate 141, figs. 1, la, lb, 2. 



Corallum composed of rather thick branches, apices bluntish, or at 

 least not acuminate. The specimen (the holotype) represented by 

 plate 141, figure 1, is 58 mm. long; the diameter of its lower end is 13 

 mm. ; upper end broken, compressed, 20 mm. wide, lesser diameter of 

 fracture 8 mm.; diameter of end of a new lateral branch not yet 

 fully formed about 4.5 mm. The diameter of the lower end of the 

 specimen (paratype) represented by plate 141, figure 2, is 15 mm. 



As the axial corallites are broken their characters are not known. 

 Radial corallites of two kinds, protuberant and immersed or subim- 

 mersed. Protuberant corallites ascending, appressed, tubular, slightly 

 compressed. Length as much as 4 mm., about 2.5 mm. probably an 

 average; all intermediate lengths down to the immersed corallites. 

 Greater diameter ranges from 2 up to 3.5 mm.; lesser diameter from 

 2 to 2.5 mm. Distance apart in vertical rows or spiral from 1 to 2.5 

 mm.; in horizontal plane, from 1.5 to 3 mm. Lower wall better 

 developed than the upper, texture rather loose, of moderate thickness, 

 outside strongly costulate with synapticulae clearly visible between 

 the costules; upper edge not rounded or incurved in the cotypes. 

 Upper wall short but traceable. Apertures with margins which slope 

 downward and outward from the upper wall or they are short labiate, 

 no nariform or dimidiate apertures were observed. Two well-devel- 

 oped cj^cles of septa, primaries larger than the secondaries, upper 

 directive more prominent than the lower; in some calices apparently 

 there may be a few tertiaries. Immersed and subimmersed corallites 

 smaller and with less developed septa than the protuberant corallites 



Coenenchyma porous, granulate, reticulate, costulate, and some- 

 what flaky. 



Locality and geologic occurrence. — Canal Zone, station 20245, cross- 

 ing of Panama Railroad over Rio Agua Salud, between Bohio Ridge 

 and New Frijoles, in the Emperador limestone, collected by T. W. 

 Vaughan and D. F. MacDonald. 



Antigua, station 6854, Rifle Butts, in the Antigua formation, col- 

 lected by T. W. Vaughan. 



Type.— No. 325042a, U.S.N.M. 



Paratype.— No. 3250426, U.S.N.M. 



This species belongs to the subgenus to which Brook applied the 

 name Eumadrepora, that is, Acropora s. s., but it is not closely related 

 to Acropora muricata (Linnaeus) and its relatives, A. prolifera 

 (Lamarck) and A. palmata (Lamarck), of the Floridian and West 

 Indian region. 



ACROPORA SALUDENSIS, new species. 



Plate 141, figs. 3, 3a, 4, 4a. 



Corallum composed of relatively slender branches. The dimensions 

 of the two cotypes which are branch segments are as follows : 



