.M\l;^l,\\l) ciioLOGicAL .si'u\j:y 219 



clillii-idiitc ill oiitliiir. I'idiii wall with a narrow raised ridge rmiuing 

 d(i\\ II its (■(■niri'. ami li\c uv >i\ iiansversc and radiating rows of minute 

 j)iiiict iii'cs lyiii.i;; in rni'i'uws. A pci'i iii'cs I'diindcd di' suljovate, the outline 

 often less c'iir\cd mi ihc iio.-iciior .-idc than elsewhere. Avicularian 

 cells small, raised, \ai-i(iusly disliilnitcd, somctinios one or two and even 

 three to a zooccium; or a c^'ll may lia\c mine al all. Ooecia unknown. 

 Zooeeia U.T) lo ().(i mm. in k'n<;tli, i)/i') lo (i.;!() mm. wide; about seven in 

 4 mm. measuring lengthwise. 



The thick marginal riiu of the zooeeia and the unusual depression of 

 the front wall arc regarded as the distinctive characters. The latter 

 feature seems to occur also iu Eschariiiora immersa Gabb and Horn, a 

 species described but unfortunately not figured in their monogra})h, and 

 founded on a specimen from the Cretaceous at Timber Creek, X. J. 

 Their description leaves much in doubt, but as it is stated that the 

 zoarium forms broad, tortuous and anastomosing plates, celluliferous 

 on both faces, and that the zooeeia are arranged in regular quincunx, 

 it seems highly improbable that C. crassida can be the same species. Of 

 other Crihrilinidae known to the writer only Escharipora incrassata 

 d'Orbigny, from the Cretaceous of France, presents considerable resem- 

 blance. That species, however, grows into bifoliate expansions, has 

 larger and relatively longer zooeeia and large accessory cells ( ? vicarious 

 avicularia) not observed in C. crassula. 



Occurrence. — Aquia Foematiox. Upper Marlboro. 



Collection. — Maryland Geological Survey. 



Family ESCHARIDAE. 



Genus LEPRALIA Johnston. 

 Lepealia subplaxa n. sp. 

 Plate LIX, Figs. IT, IS. 

 Description. — Zoarium, as seen iu three specimens, forming a hollow 

 cylinder, composed of numerous layers, each 0.3 to 0.35 mm. in thick- 

 ness, and varying in diameter according to the number of layers from 

 7.0 to 13.0 mm. Zooeeia not very regularly arranged, sometimes subo- 

 vate, at other times hexagonal or subquadrate, longer than wide, the 

 length averaging about 0.45 mm. Upper surface nearly flat, the outline 



