504 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



There is irregularity in the number and arrangement of the septa 

 resulting from the formation of new calices by fission. They are 

 usually rather thick and in many calices are bent in an irregular way. 

 In fully developed calices there are 12 septa with the usual solitary 

 directive, four lateral pairs, and a directive triplet. The laterals of 

 the triplet are more or less free from the directive of the group, but 

 usually appear to converge toward its inner end. Septal granules 

 irregular in development, rarely forming a definite, clear-cut ring, 

 more or less attached to the wall. Pali from six to eight in number, 

 irregular in development. No definite outer synapticular ring, but 

 a few synapticulae correspond in position to the septal granules ; palar 

 synapticular ring better developed. 



There is a columellar tubercle rising in the middle of an irregular 

 columellar tangle. 



Locality and geologic occurrence. — Canal Zone, stations 6015 and 

 6016, quarries in the Emperador limestone, Empire, collected by 

 T. W. Vaughan and D. F. Macdonald. 



Type.—^o. 325063, U.S.N.M. 



Paraiy pes. —'^ OS. 325064, U.S.N.M. (2 specimens). 



The type and three other specimens are plates with imdulations or 

 low gibbosities on the sides. This growth-form grades into nodose 

 columns (see pi. 148, fig. 1, for growth habit, and fig. 2 for an enlarged 

 view of the calices of another specimen of similar growth-form). As 

 the good suite of specimens shows that these are only intergrading 

 growth-forms of the same species and as they occur together at sta- 

 tion 6016, separate nomenclatorial designation appears unnecessary. 



PORITES ANGUILLENSIS, new species. 



Plate 149, figs. 1, la, 16 (type); plate 150, fig. 5. 



The following is a description of the type: Corallum composed of 

 thin, more or less undulate, separate laminae, resting one on another. 

 The underside epithecate to the edge, the epitheca minutely, regularly, 

 and concentrically striate. The type-specimen consists of two such 

 laminae, both broken. The greatest thickness of the two is about 

 15 nun., the greatest width 58 mm. One lamina is 5 mm. thick in its 

 thickest portion, the edge is thinner. 



The calices are shallow, subcircular, 1.7 to 2.3 mm. in diameter, 

 separated by flat coenenchymal walls, 0.8 to 1 mm. a.cross. The 

 coenenchyma is perforate, but rather compact and costate. 



Septa rather thick, normal number 12, with sohtary directive, 

 four lateral pairs, and the laterals on the sides of the principal direc- 

 tive loosely fused to it or continued to the columella tangle. Pah, 

 usually six in number, before the lateral pairs, on the ends of the 

 sohtary and principal directives. As a rule, there is a prominent 

 dentation at the inner edge of the waJl. Synapticulae well developed, 



