GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 397 



The oalicles are more closely crowded on the lobules, especially at the obtuse summits, 

 where they become ans^ular and are separated by thin walls and cellular exotheca. 

 Elsewhere the calicles are nearly circular, scarcely elevated, and separated by 

 exothecal spaces usually about equal to the radii of the calicleR, but tow^ard the base 

 often equal to their diameters. The exotheca and walls are very solid in most parts. 



The 24 costae are subequal, thickened, only slightly raised, faintly or almost micro- 

 scopically granulated: those of adjacent calicles are usually separated at the surface 

 by a slight intermediate groove, forming polygonal areas around the calicles. The 

 exotheca is nearly level \vith the edges of the walls and costae, flat or slightly concave, 

 minutely gYanulateJ or nearly smooth, sometimes slightly vesicular at the surface, 

 but usually almost solid and blended with the costae and walls; near the tips costae 

 imite and exotheca is cellular. 



In a transverse section, near the surface, the entire partition between the calicles 

 may be perfectly solid, whether thick or thin, but in many cases one or two rows of 

 small, rounded or crescent-shaped vesicles can be seen, and sometimes, close to the 

 surface, vesicular dissepiments are visible between the small costae, while close to 

 the basal margin of the coral the exotheca may be decidedly vesicular, appearing 

 almost like miniature honeycomb in transverse sections. But this basal portion is 

 formed by the thin, down-growing margin, where the new calicles are very short, 

 oblique, and far apart, as in many other corals that have a thin, proliferous margin. 



The septa are generally 24, subequal, jn three regular cycles; those of the first two 

 cycles are nearly equal in height and thickness; those of the third cycle are thinner 

 and narrower, and generally bend to the right and left in pairs to join the straight 

 septa of the second cycle, usually at a point more than half way to the columella, and 

 often veiy near it. The summits of all the septa are narrow and only slightly raised 

 above the walls. The edges are irregularly serrulate, two to four of the basal teeth 

 being the larger. The sides are distinctly granulated. The septa are all thin, but 

 slightly thickened toward the wall, and all are narrowed above the base, so as to leave 

 a cup-like calicular cavity. The columella is small, trabecular, papillose, and often 

 nearly wanting. In transverse sections of some calicles it is solid, and formed by the 

 union of the inner edges of the septa, but in most it is small, porous, trabecular. 



Diameter of the calices 2.5 to 3 mm.; breadth of intercalicinal spaces, usually 1 to 2 

 mm., sometimes 3 to 4 mm. or more, near the base. 



Origin uncertain, supposed to be West Indies. Several irregular gibbous masses 

 of this species, 3 to 5 inches in thickness, in the American Museum, New York, were 

 found near Osprey, West Florida, cast on the beach, after a storm, by R". P. W^hit- 

 field (No. 485). ^ I have also seen specimens from Key West. 



Verrill keeps 0. hyades and 0. excelsa separate, with the remark, 

 however, that "they may eventually prove to be one species." The 

 differences between the two consist in the latter possessing a much 

 more solid exotheca and more developed costae. There is m the 

 United States National Museum a moderate suite of specimens from 

 the hving Florida reefs, and a large nimiber of fossil specimens. I 

 feel convinced that the two forms are only variations of the same 

 species, as in the samo specimen the exotheca may be solid or vesicular; 

 and the costae may be confined to the corallite peiiphery or extend 

 from the periphery of one coralhte to that of the next. Although 

 Professor Verrill's descriptions are so comprehensive as to render a 

 new one unnecessary, I should like to call attention to some features 

 not considered in detail by him. The costae seen on the surface 



