BRYOZOAN FAUNA OF VINCENTOWN LIMESAND 19 



Genotype. — Ellisinidra (Membrampora) levata Hincks, 1882 (not 

 Norman, 1903). 



Range. — Cretaceous (Senonian), Recent. 



Historical. — Miss Hastings, 1930, has shown that Merribranipora 

 levata Norman, 1903, the genotype of Ellisina, is not the species of 

 Hincks, 1882. She gives two good figures of the two species and 

 shows the differences. In Norman's specimens the avicularia are 

 adventitious, situated on the proximal gymnocyst. In E. levata 

 Hincks they are vicarious, though small, and connected with the 

 surrounding zooecia by pore chambers. Moreover, they depend abso- 

 lutely from the proximal zooecium, which they constantly crown. 

 We suppose then that they are necessary in the opening of the oper- 

 cular valve. As this function appears to us indispensable in the 

 life of the cell, we have made Hincks' species the type of our new 

 genus Ellisinidra. 1 



Membranipora laximaculata Levinsen, 1925, from the Senonian 

 of Rugen belongs to this genus. Likewise Amphiblestrum spicu- 

 losum Ulrich, 1901, from the lowest Eocene at Upper Marlboro, 

 Md., might be classed there, but it forms with Reptoflustrella heter- 

 opora Gabb and Horn, 1862, a group with cells bearing a cryptocyst. 



ELLISINIDRA HETEROPORA Gabb and Horn, 18G2 



Plate 1, Figure 8 



1862. Reptoflustrella heteropora Gabb and Horn, Journ. Acad. Nat. Sci. Phila- 

 delphia, ser. 2, vol. 5, p. 12, pi. 20, fig. 50. 



1907. Amphiblestrum heteropora Ulrich and Bassler, in Weller, Geol. Surv. 

 New Jersey, Paleontology, vol. 4, p. 333 (bibliography). 



1920. Amphiblestrum heteropora Canu and Bassler, U.S.Nat.Mus. Bull. 106, 

 p. 158, pi. 1, figs. 11-13. 



Description. — The zoarium encrusts shells and other Bryozoa, 

 principally fragments of Ooscinopleura. The zooecia are distinct, 

 adjacent, elongated, oval, enlarged distally; the mural rim is salient, 

 thin; the cryptocyst is shallow, very little convex, slightly granu- 

 lated. The opesium is terminal, elongated, semielliptic with a prox- 

 imal border slightly concave. The ovicell is hyperstomial, embedded 

 in the distal zooecium, closed by the operculum, very convex, smooth. 

 The distal avicularium is small, triangular, transverse or oblique 

 with two small denticles for a pivot. 

 Measurements. — 



. (£3 = 0.54 mm. - . \ho = 0.27-0.3 mm. 



Z ° OeC1 > = 0.22-0.3 mm. °P CSllm > = 0.18-0.25 mm. 

 28 zooecia in 4 sq. mm. 



1 We employ whenever possible the termination idra for a genus that has a hyper- 

 stomial ovicell closed by the operculum and ina for that in which the ovicell is endo- 

 zooecial. 



