NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
429 
AIMULOSIA CLAVULA, new species. 
Plate 9, figs. 13-16. 
Description. — The zoarium incrusts bryozoa and shells. The zooecia are 
distinct, short, a little elongated; the frontal is smooth, convex, surrounded with 
large, triangular areolae. The apertura is semilunar with a concave poster. The 
ovicell is large, globular, hyperstomial ; it is opened largely above the apertura. 
Fig. 127. — Genus Aimulosia Jullien, 1888. 
A-C. Aimulosia australis Jullien, 1888. A. Zooecia, X 25. B. Polypide in place seen from 
the dorsal face, X 220. It is rather strange that often in the digestive apparatus of bryozoa 
the stomach shows as an appendage of the esophagus, and that the latter appears to replace 
in its abnormal volume the functions of the stomach (gastroid esophagus). C. Avicularium of 
the frontal face with its two muscles, X 120. (After Jullien, 1888.) gt, tentacular sheath; 
mav, elevator muscle of the avicularian mandible ; mr, large retractor muscles of the polypide ; 
oes, gastroid esophagus ; ph, pharynx ; t, tentacles. 
The frontal avicularium is adjacent to the apertura; it is small, round, with pivot, 
and it opens externally. 
M easurements .- — Apertura 
j ha— 0.10 mm. 
17,7=0.12 mm. 
Zooecia 
\Iz=z0 . 50 mm. 
1 7^=0.25-0.30 mm. 
Variations . — The areolae are originally small (fig. 15) ; they become larger in 
becoming funnel shaped (fig. 13). They probably allow to pass the endocystal 
buds, which are developed above the frontal and which deposited an irregular 
pleurocyst (fig. 15). Very frequently the ovicell is wider than the zooecium, which 
thus assumes the form 'of a nail. 
