NORTH AMERICAN EARLY TERTIARY BRYOZOA. 595 



FIG. 176. Anatomical structure of the family Celleporidae Busk, 1852. 



A-C. Free larva of ScMsmopnra 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 in 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 atter Barrels, 1877.) c, corona; cd, 

 digestive cavity; est, stomach; fl, flagellum : mi, aboral mesoderm; ms, oral (labial) mesoderm; 

 o, ciliated cleft: pji, pharynx; pj, vibratile plume; si, furrow of separation. 



D-G. Anatomical structure of OstJiimosia 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.) or, avicularium ; l>a, 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 ; 7-, rectum : t, tentacles. 



H. Holoporella alHrostris Smitt. 1867. Polypide showing the long oral (vaginal) glands. X 

 85. (After Waters, 1913.) 



I. Schismopora pumicosa Busk, 1S54. Glandular vaginal organ (oral glands of Waters). 

 Longitudinal section. (After Calvet, 1900.) 



J, K. Costazzia costata MacGillivray, 186S. The muscles are attached to the opereulum 

 and the avicularian mandible. (After MacGillivray, 1888.) 



L. Holoporella apiculata Busk, 1884. Chitinous appendages. 



M. f-chismopora bidentictilata, var. subacqualte Busk, 1884. Chitinous appendages. (L, M 

 after Busk. 18S4.) 



N-P. Schismopora coronopus Wood, 1850. X. Portion of a zoarium, X 24, showing termi- 

 nology. (After Jullien, 1903.) O. Mandible of the interzooecial avicularium, X So. P. The 

 avicularian mandible of the frontal avicularium, X 85. (O, P after Waters, 1885.) 



