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BULLETIN 125, UNITED STATES NATIONAL MUSEUM. 



/a 





FiQ. 3. — Genus CAopmo Jullien, 1881. 

 Figs. A-G. Chaperia acanthina Quoy and Gaymard, 1824. 



A. Interior of a zooecium shoxving the polypide and the retractor muscles of the operculum. These 

 are the two enormous muscular bundles which characterize the family Chaperiidae, determining in 

 the zooecia the formation of the calcareous lateral plates situated below the orifice. Such plates are the 

 most characteristic remains of this anatomical arrangement which existed as far back as the Creta- 

 ceous period. 



B. A young colony, X "0, treated with "eau de javelle," showing the ancestrula with the base of 

 the spine of the circumference. In this ancestrula the two lateral funnels which serve for the insertion 

 of the retractor muscles of the operculum, can be seen. 



C. Diatoms and radiolaria found in the digestive apparatus of this species, X 216. The radiolarian 

 is Dyctioca specuhan Ehrenberg, a species encountered in many other bryozoa. 



D. Very young zooecium bearing spines and in the orifice of which the funnels in process of forma- 

 tion, still unseparated, can be seen. 



E. Zooecia covered over by the ectocyst and bearing marginal spines. (Figs. A-E, after Jullien, 

 1888.) 



F. Operculum (after Kirkpatrick, 1890). 



