GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 417 



Genus MAEANDRA Oken. 



1815. Maeandra Oken (part), Lehrb. Naturg., Th. 3, Abth. 1, p. 70. 

 1902. Maeandra Vekrill, Conn. Acad. Arts and Sci. Trans., vol. 11, p. 66. 

 1917. Maeandra Vaughan, Carnegie Inst. Washington Pub. 213, p. 119. 



Type-species. — Madrepora labyrinihiformis Linnaeus. 



MAEANDRA ANTIGUENSIS, new species. 



Plate 103, figs. 3, 4, 4a. 



The general habit of the corallum is similar to that of Maeandra 

 clivosa (Ellis and Solander), that is, the upper surface is more or less 

 lobulate, not rather uniformly rounded or domed as M. strigosa 

 (Dana). A view of the upper surface of each cotype is shown on 

 plate 103, figures 3, 4. Valleys sinuous, relatively long, as much as 

 or more than 26 mm. in length; width from 3.5 to 5.5 mm., about 

 4.25 mm. usual; depth about 2 mm. Collines with narrow, acute or 

 subacute summits, the septa sloping away at an angle of about 45°. 

 Adjacent valleys are usually separated by simple walls; in places 

 separate mural edges are distinguishable, but in such instances the 

 distance between the walls is less than 0.5 mm. 



Septa decidedly crowded, 8 or 9 long septa and as many interme- 

 diate short septa within 5 mm., that is, from 32 to 36 septa, alternately 

 short and long, within 1 cm. The long septa extends to edge of the 

 columellar fossa; the intermediate septa are about half as long. 

 Septal margins finely dentate, about 10 small teeth on the long septa; 

 slope downward and inward at an angle of about 45°, as previously 

 stated. Inner ends of long septa more or less thickened, some appear 

 to bear paliform lobes, fused by lateral expansions and processes at 

 the edge of the columellar fossa. 



Columella composed of axial septal processes, which are usually 

 more or less flattened and curled. Calicinal centers indistinct. 



Thin, crowded, endothecal dissepiments abundant. 



Localities and geologic occurrence. — Antigua, station 6881, Antigua 

 formation, Willoughby Bay, cotypes, 2 specimens, collected by 

 T. W. Vaughan. 



Panama, station 6587, Tonosi, a broken specimen, collected by 

 D. F. MacDonald. 



Cotypes.— No. 325003, U.S.N.M. 



Maeandra antiguensis is very close to M. clivosa. The principal 

 differences seem to be the steeper margins and the thicker inter- 

 corallite walls, and the slightly wider and deeper valleys of M. 

 clivosa. The cotypes of M. antiguensis were compared with 33 small 

 specimens of M. clivosa and the differential characters indicated 

 appear valid. 



The specimen obtained by Doctor MacDonald is only a fragment, 

 but as the cross-section of the corallites and walls and the septal 



