GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 



339 



Calicular margins obscurely or not at all elevated; without a pro- 

 tuberant upper lip. 



Septa, six distinct primaries, about equal in size, extend to the 

 columella; secondaries much smaller, but can be distinguished in 

 the better preserved caiices. 



Columella a small, slightly compressed, fairly prominent style. 



Coenenchymal surface closely set with pointed granulations. 



Locality and geologic occurrence. — Canal Zone, at stations 6016, 

 quarry in the Emperador limestone, Empire, Canal Zone, collected 

 by T. W. Vaughan and D. F. MacDonald; 6026, in the Culebra 

 formation, 2J miles south of Monte Lirio, Panama Railroad (relocated 

 line), collected by T. W. Vaughan and D. F. MacDonald. 



Cotypes.— No. 324767, U.S.N.M. (3 specimens) . 



Stylophora goethalsi resembles the Santo Domingan species, S. minor 

 Duncan, which is ramose and has small caiices, from 0.5 to 0.75 mm. 

 in diameter. The end of the branches in S. goethalsi are more com- 

 pressed than in S. minor, its caiices are slightly larger, and its 

 secondary septa arc better developed. Although closely related, 

 they appear to belong to distinct species. 



STYLOPHORA MACDONALDI, new species. 



Plate 75, figs. 5, 5a, 6, 6a, 7, 7a. 



Corallum composed of elongate, slender, curved branches and 

 branchlets, with bluntish, rounded summits. The only branch 

 terminal that is perfect is represented by plate 75, figure 5. The 

 following are measurements of four broken branches: 



Measurements in millimeters of branches of Stylophora macdonaldi 



Branch No. 



Length. 



Diameter of 

 smaller end. 



Diameter of 

 larger end. 



1 



15.5 

 19.0 

 21.5 



3. 5 by 5.0 

 4.0 by 6.5 

 4. 5 bv 5. 



5. by 5. 3 



2 



5. 5 by 7.5 



3 



5.0 by 6. 5 



4 



28. 4. bv 4. 



4. 5 by 5. 5 











Just below the place of bifurcation the parent branch is consider- 

 ably compressed; in one branch the greater diameter below a fork 

 is 12 mm., while the lesser diameter is only 6.5 mm. 



Caiices rather shallow, but distinctly excavated; diameter, 1 mm.; 

 distance apart from 0.5 to 1.5 mm., usually less than the calicular 

 diameter; margins usually slightly or not at all raised, but knots 

 correspond to the outer ends of the septa. There is no upper lip to 

 the caiices. 



Septa, six well-developed, strong, subequal primaries extend to 

 the columella; secondaries small but usually distinct. Subequal 

 knots correspond to the outer ends of th^ two cycles of septa, and a 



