394 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



of small costae between the larger ones, similar to those of 0. cavernosa 

 var. endothecata, and there are a few quaternary septa. Columella 

 rather small. 



. I did not collect any specimen of this species in Antigua. The 

 species to which I am applying the name 0. canalis is very nearly 

 related and may eventually become a synonym. However, the 

 primary and secondary septa are more nearly equal in 0. intermedia 

 than in 0. canalis. 0. costata and 0. insignis are both very similar 

 to 0. canalis. O. costata has more extended costae, and 0. insignis 

 has larger calices and, in comparison with the size of the calices, 

 fewer septa. As suites of specimens adequate for a satisfactory 

 study of variation are not available, at least temporarily, the three 

 names, 0. intermedia, 0. costata, and 0. insignis should be treated as 

 valid. 



Locality and geologic occurrence. — According to Duncan, "From 

 the upper Parian of Trinidad (Wall and Sawkins coll.), and the marl- 

 formation [Antigua formation] of Antigua." The specimen repre- 

 sented by plate 97, figure 2, is from Antigua. 



15. ORBICELLA GABBI, new species. 



Plate 108, figs. 1, lo, 16. 



Corallum massive; corallites very large, from 20 to 25 mm. in 

 diameter, by far the largest corallites of any species of the genus 

 known from the American Tertiary formations. Intercoralhte areas 

 narrow or as much as 4.5 mm., perhaps more, across. 



Septa very numerous, thin, crowded, 106 were counted in the 

 corallite represented by plate 108, figure la. There are more than 5 

 complete cycles. Septal grouping obvious, usually every other or 

 every fourth septum reaches the columella, but in places there are 

 seven or eight shorter septa, forming a group, between two long 

 septa. 



Columella rather small, only about 2.5 mm. in diameter. Endo- 

 thecal and exothecal dissepiments greatly developed, thin-walled. 



Locality. — Santo Domingo (Gabb Collection). 



Type. — Academy of Natural Sciences of Philadelphia. 



16. ORBICELLA IRRADIANS (Milne Edwards and Haime) Vaughan. 



Plate 97, figs. 3, 3a. 

 1848. Phyllocoenia irradians Milne Edwards and Haime, Comptes Rend., vol. 



27, p. 469. 

 1860. Phyllocoenia irradians Milne Edwards and Haime, Hist. nat. Corall., 



vol. 2, p. 272. 

 1868. Phyllocoenia irradians Reuss, K. K. Akad. Wissensch. Wien, Math.- 



Naturw. GL, Denkschr.,.vol. 28, p. 156, pi. 10, figs. 5-7; pi. 11, figs. 1-3. 



This appears to be the species referred to by Fabiani in his "II 

 paleogene del Veneto"^ as Heliastraea irradians Michelin. Michelin 

 erroneously applied the name Astrea radiata^ to this species. 



1 R. Univ. Padova Inst, geolcg. mem., vol. 3, pp. 225,^230, 231, 1915. 



