42 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 16 



ones rather thin, only little thickened even at the margin, roughly gran- 

 ulous on the sides ; their costal prolongations elevated and rather thin. 

 Smaller septa about half as wide, a little thinner and less elevated, as are 

 also their costal prolongations. Columella a small tubercle, often prom- 

 inent, sometimes flattened. Internal structure as in the preceding, but 

 the transverse septa are nearer together. 



"The largest specimens are ten inches to two feet in diameter; and 

 often a foot thick or high; some of the prominences or lobes are from 

 four to six inches in diameter, and nearly as high; diameter of cells 

 mostly .05 to .06 ; distance between them ordinarily .05 to .08. 



"Pearl Islands, at extreme low-water of spring tides, — F. H. 

 Bradley." 



The specimens from Sta. 23-33 is a small frondose fragment which 

 is epithecate on one side, possibly indicating early stages of growth before 

 the corallum becomes massive. 



Hypotype: Cat. no. 12.1 (Sta. 23-33). 



Material examined: Sta. 23-33 (1). Bottom sample 503 (frag.). 

 Cat. nos. 12.1-12.2. 



Distribution: Ofi La Plata Island and La Libertad, Ecuador. 

 Bathymetric range, 10-19 fms. 



Pavona (Pavona) cf. explanulata (Lamarck) 

 Plate 2, fig. 13 



Agaricia explanulata Lamarck (1816), Hist. Nat. Anim. sans Vert., 

 vol. 2, p. 244; Milne Edwards and Haime (1851), Ann. Sci. 

 Nat., sen 3, vol. 15, p. 124. 

 Lophoseris explanulata Lamarck, Milne Edwards (1860), Hist. Nat. 

 Corall., vol. 3, p. 69, pi. D 1 1, fig. 2. 



Two small fragments appear to resemble Lamarck's species. Calices 

 small, the largest being 2 mm in diameter, separated by gently convex 

 ambulacra; septa 20-22, subequal, granulated, about half extending to 

 the center of the calice; columella small, styliform. Better material 

 might show this to be a new species. 



Worn, fragmentary materials representing 4 or 5 species of pavonid 

 and leptoserid corals are present in Bottom sample 329. 



Pavona explanulata is an Indo-Pacific species. 



Hypotype: Cat. no. 13.2 (Bottom sample 427). 



Material examined: Bottom samples 329 (1), 427 (1). Cat. nos. 

 13.1-13.2 



Distribution: Chatham Bay, Cocos Island, 40-46 fms; Clipperton 

 Island, no bathymetric data. 



