418 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



characters agree with M. antiguensis, there is no reasonable doubt as 

 to its belonging to that species. 



MAEANDRA PORTORICENSIS, new species. 



Plate 107, figs. 1, la. 



Corallum massive, composed of long valleys, from 5.5 to 9 mm. 

 wide, and about 3.5 mm. deep, separated by acute collines. Walls 

 in the collines, rather thick but simple. 



Septa, rather thick, crowded, about 10 in 5 mm., or 20 to the 

 centimeter. As a rule alternately shorter and longer, but in some 

 places they are equal. At the wall usually equal in thickness. The 

 inner ends of some septa are enlarged, and there are indications that 

 such septa bear upright paliform teeth. Margins dentate. Calicinal 

 centers indistinct. 



Columella absent. 



Locality and geologic occurrence. — Four miles west of Lares, Porto 

 Rico, Pepino formation, collected by R. T. Hill. 



Type.— No. 325004, U.S.N.M. 



Remarks. — Maeandra portoricensis is very close to an undescribed 

 species from the St. Bartholomew Eocene, to which Duncan erro- 

 neously applied the name Manicina areolata (Linnaeus). The differ- 

 ence seems to lie in the former having straighter valleys (a character 

 of very little value), and thicker septa and walls. 



MAEANDRA DUMBLEI, new species. 



Plate 104, figs. 1, la. 



Corallum massive, upper surface gradually curved, without gib- 

 bosities. The type, a segment of a head, is 63 mm. long, 57 mm. 

 wide, and 45 mm. thick. 



Valleys straight or curved; length from 5 mm., the diameter of 

 a solitary calice, up to 30 mm. or even more; width from 3 to 5 mm. ; 

 depth 1.5 mm. or less, the valleys are very shallow, almost super- 

 ficial Collines flat or furrowed along the top; width from 1.5 to 2.5 

 mm. Each of two adjacent series usually with its own separate 

 wall, the walls separated on top by a slight depression which is 

 crossed by costae. The colline characters are those characteristic 

 of Diploria, which is typical Maeandra. 



Septa rather distant, 9 within 5 mm. or 18 to 1 cm.; subequal 

 or alternately longer and shorter, the shorter usually almost reach- 

 ing the columella; no rudimentary septa except in young calices; 

 outer septal ends thick. Septal margins broken in the type, but 

 the trabeculae indicate fairly large dentations, about 5 on a long 

 septum outside the distinct, thickened, palar lobe. 



Columella composed of septal processes, only slightly developed. 

 Calicinal centers distinct or obscure. 



