36 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



The genera Cea^ Semicea^ and Filicea of D'Orl)igny are distin- 

 guished only by zoarial differences and ought to be united into 

 a single genus. The genus Reptocea requires further examination. 

 The genus Laterocea is peculiar for its tubes are cylindrical and not 



Cea (Filicea) regularis D'Orbigny, 1852. 



A. Transverse section, X 16, showing the thick zoarial walls. The section 

 cuts the branch a little above the bifurcation of the central tube which is thus 

 represented by a small pore. 



B. Central part of a transverse section, X 16, .showing the central tube replac- 

 ing the basal lamella. 



C. Another transverse section, X 16, with the central tube surrounded by a 

 circle of tubes of the same diameter, all of which replace the basal lamella. 



D. Longitudinal section, X 16, there are two central tubes (1, 3). Tube 1 

 divides to form tube 2 which in turn gives rise to tube 4. The cross section of 

 figure B is along the line through the middle of the section while that of figure 

 C is through the top ijart. The walls are much thickened at their extremity 

 and bear an oval projection which may be transformed into a perforated dia- 

 phragm. 



E. Structure of the zooecial walls at the extremity X 50, showing a monili- 

 form, central, clear space surrounded by laminated tissue. 



Cretaceous (Coniacian) ; Villedieu (Loir-et-Cher), Prance. 



club-shaped. The study which we have made of this genus, in 

 which the ovicell is identical with that of Cea, shows at once that 

 the form of the tubes is only a generic character. Following are the 

 new generic diagnoses. 



