12 PROCEEDINGS OF THE NATIONAL, MUSEUM. vol.61. 



Various forms of growth are represented in the species with the 

 ovicell of Mecynoecia^ but the majority have the Entalophora zoarial 

 form— that is, an erect ramose growth with the zooecial tubes open- 

 ing on all sides. Other species of Entalofliora^ however, have ovi- 

 cells characteristic of two other families, and still others show no 

 ovicell at all. The ovicell of the genotype of Entalophora^ E. cel- 

 larioides Lamouroux, 1821, is unknown, so, following our custom, we 

 retain the name Entalophora as a zoarial form for species showing 

 no ovicell. 



MiECYNOECIA GRACILIS, new species. 



Plate 4, fig. 4. 

 Description. — The zoarium is free, unilamellar ; the zone of growth 

 is thin and narrow. The tubes are distinct, separated by a small 

 furrow, somewhat convex, slender^ terminated by a rather long peris- 

 tomie; the aperture is elliptical, or orbicular; the peristomes are 

 thin, little separated from each other. The ovicell is small, elongated, 

 convex, smooth ; the oeciostome is somewhat smaller than a peristome. 



[ Diameter of aperture 0. 08- . 10 mm. 



Diameter of peristome (=zoo- 



Measurements.— \ ecial) .16 mm. 



Distance of peristomes .64:- .80 mm. 



Separation of peristomes .56 mm. 



Aiflnities.—ln the general aspect of its tubes this species resembles 

 Tngonoecia verrucosa Milne Edwards, 1838, but it differs in its 

 smaller micrometric measurements, in its free zoarium, and in the 

 form of its ovicell. 



We owe the figured specimen to the kindness of Mr. Edwin A. Wal- 

 ford of Banbury, England. 



Occurrence.— Jurassic (Bathonian) : Shipton Gorge, Dorset, Eng- 

 land. 



Holotype.— Cat. No. 68902, U.S.N.M. 



MECYNOECIA OBESA, new species. 



Plate 1, tigs. 6-S. 

 Description.— The zoarium has the cylindrical, branching Entalo- 

 phora form of growth enlarged at the bifurcations. The tubes are 

 thin, long, cylindrical, regular, convex, striated transversally, ter- 

 minated at their extremity by a peristomie somewhat upward bent 

 and very salient. The oeciostome is thin, orbicular, oblique. The 

 ovicell is enormous, very globular, elongate, elliptical, striated trans- 

 versally by large wrinkles; the oeciostome is transverse, elliptical, 

 orthogonal, somewhat wider than the tubes. 



Diameter of tube and of peris- 

 tome ^- 1^ n^- 



Measurements.— {j^.^^^^^^^ between orifices 0.58-1.00 mm. 



Separation of peristomes .66 mm. 



