116 EOCENE AND LOWER OLIGOCENE CORAL FAUNAS. 



Genus OCULINA Lamarck. 



The followiug notes on Oculina diffusa of the West Indies may be of 



interest in this connection. The wall is a true theca (PI. II, fig. 5), i. e., 



there are separate centers of calcification in the wall, which is not formed 



by the fusion of the distal ends of the septa.^ The septa are solid, and are 



composed of ascending trabeculae, with a line of divergence about coinciding 



in position with the wall. The margins, due to projection of the trabecular 



axes, are minutely dentate. The pali are lobes near the inner ends of the 



septa. The columella is false, formed by the fusion of septal pi'ocesses. 



Reproduction takes place by both lateral budding and by fission (septal 



budding, dividing the mother calice into two daughter calices of the same 



size). 



Oculina vicksburgensis (Conrad). 



PI. X, figs. 4 to 10. 



1847. Madrepora riclcshurt/ensis Conrad. Proc. Acad. Nat. Sci. Phila., Vol. Ill, p. 296, 



1848. Madrepora vicksburyensis Conrad. Jour. Acad. Nat. Sci. Pbila., 2d ser.. Vol. 



I, p. 127. 

 1850. AstroheUa lesueuri Milne-Edwards and Haime. Annales .sci. nat., 3d ser., Vol. 



XIII, p. 75. 

 1857. AstroheUa lenueuri Milue-Edwards and Haime. Hist. Nat. des Corall.. Vol. II, 



p. 112, IM. DI, figs. 8 and Sa. 

 1861. AstroheUa lesueuri de Froiuentel. Iiitrod. a I'F^tude des Polyp, foss., p. 178. 

 1881. AstroheUa lesueuri Quenstedt. Rohreu- uud Sternkorallen, p. 071, pi. clxxx, Mg. 51. 



The following is a translation of the original descrijjtion of A. lesueuri: 



Corallum dendroid, forming branches from 2 to 3 centimeters in thickness, cylin- 

 drical, sometimes coalescent, with cceneuchyma highly developed, extremely compact, 

 and whose surface, which is very finely granulated, presents in addition flexnous 

 feeble strife. Calices circular, subequal, distant once or twice their diameter or even 

 more, with thin slightly prominent margins, with a cavity of only little depth. Colu- 

 mella weak, spongy, slightly developed, but a little more than in other species of the 

 genus. Fourteen principal septa alternately unequal, extremely thin, slightly flexn- 

 ous, subgranulate, scarcely exsert. An equal number of very small septa. Diameter 

 of the calices 4 millimeters. Tertiary of the Walnut Hills, on the banks of the 

 Mississippi (Lesueur). Collection of the Museum. 



' Ortmaim, in Die Zeitschrift t'iir wisseuschaftliclie Zoologie, Vol. L, 1890, p. 309, writing of 

 Oculin.i dillnsa, says: " Oeulina hat mit den iibrigeu .sog. Ociiliuiden (AmpUihi-lia, Acrohelia, Lopho- 

 helia) absolut nicbts zu tbim, sondorn gebcirt iu die Verwandtschal't von Heliastni'a. Von ersteren 

 untersclieidet sie sich vor alien Diugi'U durch das Felileu der ephten Maner." A comparison of PI. II, 

 fig. 5, of this work, with Ortmaun's statement, shonld be made. The figure shows an undoubted 

 so-called true theca. 



