NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
595 
Fig. 176. — Anatomical structure of the family Celleporidae Busk, 1852. 
A-C. Free larva of Schismopora pumicosa Busk, 1854. A. Lateral view, X 75. showing 
the reduction of the calotte, the extension of the corona with the disappearance of the cilia 
replaced by a general covering of shorter cilia and, finally, the flattening of the oral face. 
B. View of the oral face showing the thick band of the oral mesoderm and iu the middle a small 
portion of the stomach, X 50. C. View of the aboral face showing the aspect of the calotte and 
the epithelial structure of the stomach, X 50. (A-C after Barrois, 1877.) c, corona; cd, 
digestive cavity; est, stomach; fl, flagellum; mi, aboral mesoderm; ms, oral (labial) mesoderm; 
o, ciliated cleft ; ph, pharynx ; pi, vibratile plume ; si, furrow of separation. 
D-G. Anatomical structure of Osthimosia evexa Jullien, 1888. D. Zooecium viewed pos- 
teriorly. The funiculus seems to exist after the stomachic caecum, X 150. E. An isolated 
zooecium. The buds of the endocyst have developed to produce an avicularian cavity and to 
lodge in the areolar pores of the frontal face, X 115. F. A larva in its ovicell, after decalci- 
fication of the zoarium, X 75. G. Arrangement of the muscles in the avicularian cavity. 
(D-G after Jullien, 1888.) av, avicularium ; ba, buds of the areolar pores; coe, stomachic 
caecum; mb, muscular bundles; mo, occlusor muscles of operculum; mp, parietal muscles; mr, 
large retractor muscles of the polypide; r, rectum; t, tentacles. 
H. Holoporella albirostris Smitt. 1867. Polypide showing the long oral (vaginal) glands, X 
85. (After Waters, 1913.) 
I. Schismopora pumicosa Busk, 1854. Glandular vaginal organ (oral glands of Waters). 
Longitudinal section. (After Cal vet, 1900.) 
J. K. Costazzia costata MacGilliyray, 1868. The muscles are attached to the operculum 
and the avicularian mandible. (After MacGillivray, 1888.) 
L. Holoporella apiculata Busk, 1884. Chitinous appendages. 
M. Schismopora bident iculata, var. subaequalis Busk, 1884. Chitinous appendages. (L, M 
after Busk, 1884.) 
N-P. Schismopora coronopus Wood, 1850. N. Portion of a zoarium, X 24, showing termi- 
nology. (After Jullien, 1903.) O. Mandible of the interzooeeial avicularium, X 85. P. The 
avicularian mandible of the frontal avicularium, X 85. (O, P after Waters, 1S85.) 
