280 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
The aperture is semilunar or ogival and is surrounded by a prominent peristome; 
its proximal border is straight with two small lateral slits ; there is a vestibular arch. 
Measurements. — Aperture 
|/m=0.08 mm. 
|.7«=0.06 mm. 
„ . f Za= 0.44-0.46 mm. 
Zooecia , 
[72=0.20 mm. 
Breadth of the segments 0.20-0.36 mm. 
Affinities. — This species is articulated as in Cellaria; but in its other charac- 
teristics it is nearer to Macropora. As in that genus, there is a peristome, an oral 
arch, and two oral slits. We have not seen an ovicell. It is impossible to estab- 
lish a new genus on such insufficient material as we possess, since the figured 
specimens are the only ones which have been found. We dedicate this species to 
Dr. Frank Burns, who collected many species of Tertiary 
bryozoa for our study. 
Occurrence. — Middle Jacksonian (Castle Hayne limestone) : 
Wilmington, North Carolina (very rare). 
Holotype.- — Cat. No. 64014, U.S.N.M. 
Suborder Ascophora Levinsen, 1909. 
The zooecial hydrostatic system is a sack or compensatrix 
placed under the frontal and in which the sea water is intro- 
duced. The parietal muscles are attached to this sack. 
The COSTULAE. 
(Family CRIBRILINIDAE Hincks, 1880.) 
The zooecia have their frontal wall formed of flattened 
ribs ordinarily hollow, radiating from the outer border 
toward the median line of the zooecia, where they are intimately joined together; 
these ribs are united to one another, sometimes by a more or less large number of 
transverse passages, and sometimes border to border, the ribs, however, always 
remaining apparent. 
This family is not natural, for its essential characters are too much at variance. 
We indicate, therefore, the anatomical bibliography for each of the genera studied. 
In the future, these genera will probably be distributed in the Malacostega and 
Ascophora. The anatomical researches published have shown the presence of a 
compensatrix, for which reason we classify the group in the Ascophora; but we 
recognize that certain genera are unprovided with this organ. 
Terminology. — The internal structure of the Costulae has been carefully studied 
by Norman. 1 The costula (A) (bar of Norman) always has its proximal extremity 
rounded (fig. 80), forming the loop of Norman or talon of Jullien (C). This 
structure is hollow; the hollow part is the lumen line or more simply the lumen. 
There are often openings in the lumen called lumen pores. The sides of the costules 
are the lateral lines (D) ; the pore-like openings generally developed between them 
ect 
Fig. 79. — Structure of 
the Ascophora Levin- 
sen, 1909. 
Transverse section of a 
zooecium. cs, compen- 
satrix; ect, ectocyst; fp, 
parietal fibers (muscles); 
pb , basal skeleton wall; 
pf, frontal skeletal wall . 
1 1903, Annals and Magazine Natural History, ser. 7, vol. 12, p. 90. 
