180 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Dictuonia Jullien, 1881. There are straight onychocellaria. The 

 orifice of the ovicell is not trilobate. Cretaceous. The known spe- 

 cies of this genus are Eschara echinata, E. cynara, E. elea, E. acts, 

 Vincularia tuberculata D'Orbigny, 1852, and Eschara matrona Hage- 

 now, 1839. The ovicells of all these are known. 



Among the species cited by Jullien and by Levinsen, the group 

 E. danae — E. nerei, has never afforded ovicells in spite of the large 

 number of specimens studied. The external appearances are then 

 very deceiving in this group as in all the other families of bryozoa. 



The general structure is membraniporoid and in spite of the pres- 

 ence of onychocellaria, it is altogether different from that of the 

 Onychocellidae in which the ovicell is endozooecial. This latter 

 family has numerous well characterized representatives in the 



Cretaceous. 



Genus OMOIOSIA Canu and Bassler, 1927 



The zooecia are hexagonal. The opesium perforates the crypto- 

 cyst; it is bordered by a salient thread. The accessory zooecia 

 (onychocellaria?) are quite similar to the others, but the distal 

 portion of their cryptocyst is much larger. 



Genotype. — Omoiosia (Vincularia) maorica Stoliczka, 1864. 



Range. — Miocene, Recent. 



The only other known species is Omoiosia (Melicerita) elliptica 

 Maplestone, 1900, from the Miocene of Australia. 



The ovicell not being known, a better place for this genus might be 

 in the Biflustridae. 



OMOIOSIA MAORICA Stoliczka, 1864 



Plate 21, fig. 10 



1S64. Vincularia maorica Stoliczka, Fossil Bryozoa aus dem Tertiary Griin- 

 sandstein der Orakei-Bay, Reise des Oest. Fregatte No vara, vol. 1, 

 p. 153, pi. 20, fig. 8. 



Measurements. — 



0.60 mm. 

 lz = 0A0 mm. 



„ . [7io = 0.25mm. „ • Lz 



Opesiuniw _ . _ Zooecia-',, 



r [lo = 0.15 mm. [lz = 



Structure. — The colony is bilamellar, free, of regular fronds con- 

 taining 4 longitudinal rows of zooecia on each face. The two lamellae 

 are separable. On the dorsal the zooecia are visible, rectangular, of 

 the Bifiustra type. The zooecia are hexagonal, elongated, regular; 

 the mural rim is thin and may become rounded, distally pointed; 

 the cryptocyst is shallow, smooth, and completely surrounds the 

 opesium. 



The opesium is oval, anterior (not terminal) bordered by a salient 

 pad very constant in its dimensions. This great regularity indicates 

 a very special internal structure, very different from the other recent 

 species provided with onychocellaria. 



