GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 405 



About lialf the calices on this specimen are 9 or more mm. long. 

 The large caUces are usually separated ])y narrow intercorallite areas, 

 while most of the smaller calices ai'o (Ustant from 1.25 up to as much 

 as 3.5 mm. The large calices are excavated, while the smaller are 

 shallow and are tumid around their peripheries. 



Septa thin, normally in four complete cycles; in some calices qui- 

 naries are present in a few quarter systems. The primaries are usually 

 somewhat thicker, in a few calices conspicuously thicker than the 

 members of the higher cycles, and extend to the columella; the sec- 

 ondaries iilso extend to the columella. The tertiaries may fuse to 

 the secondaries near the columella; and the quaternaries may fuse 

 to the tertiaries about halfway between the calicular periphery and 

 the columella, or the inner septal ends may be free. Septal grouping 

 not conspicuous. Septal margins with fine dentations, about 7 in 

 ] .25 mm. ; that is, a little less than 0.2 ram. from the top of one 

 dentation to that of the next. 



Columella small, in some calices represented by an axial lamella. 

 The variant represented by this specimen is abundant about three- 

 quarters of a mile south of the Cathedral in St. John, on the south- 

 west side of the Otto estate, where I obtained 11 specimens. 



Specimen No. 2, also from Station 6866, St. John, Antigua (pi. 99, 

 figs. 3, 3a). — The corallum is of tuberose shap'e and has a maximum 

 length of about 75 mm. 



This specimen resembles in its characters that part of specimen 

 No. 1 where the corallites and calices are smaller and more distant. 

 The calices are tumid around their peripheries and are shallow. The 

 usual calicular diameter, measured between the tops of the septal 

 arches, is from 4.5 to 5 mm. ; distance between calices, about 2.5 mm. 



Other characters need not be described, except to say that the 

 columella is either a compressed papilla or a short lamella. 



Specimen No. 3, from, Station 6856, Friars Hill, Antigua (pi. 100, 

 figs. 3, 3a). — The corallum of this specimen is 85 mm. long, 70 mm. 

 wide, about 75 mm. tall, and has a more or less tuberose form of 

 growth. 



The fully developed calices are 5 to 6 mm. in diameter, and are 

 usually about 2 mm. apart, with depressed intercorallite areas, and 

 slightly raised calicular rims, which project as much as 0.75 mm. 

 The free part of the corallites in places rises perpendicularly above 

 the intercorallite areas, but in other places the calicular peripheries 

 are rounded in profile. 



Septa in four complete cycles, with a few quinaries in some calices ; 

 primaries the thickest; secondaries nearly as thick as the primaries; 

 tertiaries considerably thinner; quaternaries the thinnest, unless 

 quinaries are present. There is grouping of the highest cycles around 

 the secondaries, but it is not very striking. 



