222 SYSTEMATIC PALEOXTOLOGT 



"While the appearance presented by the surface of the zoarmm is sub- 

 ject to considerable variability, the essential characters are nevertheless 

 very constant. Compared with the numerous described species possess- 

 ing a niueronate aperture, none seems to be nearer than the form 

 described by Gabb and Horn under the name Escliarifora typica. How- 

 ever, aside from the obvious zoarial differences between the two species, 

 that' one being erect and bifoliate, the surface characters of the zooecia 

 are sufficiently different to obviate all necessity for detailed comparisons. 

 Any one familiar with the fossils can scarcely fail to distinguish them 

 at a glance. The species occurs in the Cretaceous at Vincentown, IST. J. 



Occurrence. — Aquia Foemation. Upper Marlboro. 

 . Collection. — Maryland Geological Survey. 



COELENTERATA. 



Class ANTHOZOA. 



Order HEXACORALLA. 



Family TURBINOLIDAE. 



Genus FLABELLUM Lesson. 



Flabellum sp. 

 Plate LXI, Figs. 3, 3a. 



Flabellwn sp. Vaughan, 1900, Men. U. S.-Geol. Survey, No. 39, p. 66. 



Description. — " Corallum compressed cuneiform, attached by a short 

 pedicel, with slightly developed marginal wings above the pedicel. The 

 dimensions of the two largest specimens, whose outer surface is unfortu- 

 nately so very much corroded that its detail is destroyed, are: 



1 3 



iiim. mm. 



Greater diameter of calice 14 13 



Lesser diameter of calice 9 7 



Height of corallum 15 1.5 



" Distinct costae correspond to the larger septa. The number of the 

 septa was not determined with certainty, but is about forty. 



" This may be a new species, but has a suggestive resemblance to some 



