NORTH AMERICAN EARLY TERTIARY BRYOZOA. 



497 



the orifice. There is a median avicularium developed on the poster. The zoarium 

 is escharoid, flattened and branched, formed of a single layer of zooecia. 

 Genotype, Ch'yptella torquata Jullien, 1903. Recent. 



mr 



esl 



FIG. 139. Genus Hippadenella Canu and Bassler, 1917. 



A-C. Hippadenella margaritifcra Quoy and Gayruard, 1833. A. Zooecia, X 55. The primary 

 ribs of the frontal wall are seen at the bottom of the avicularia. Both the ovicells and the 

 avioularian chambers show concentric deposits of lime, X 55. (After Levinsen, 1909.) B. Sec- 

 tion exhibiting contents of avicularian chambers with double gland-like bodies and the proto- 

 plasmic mass and a section of the larger body, X 250. (After Waters, 1888.) C. Fragment of 

 decalcified zoarium, X 64, seen from the dorsal face. The growth of the polypide from the 

 young stage, figured in the upper part of the figure to the more advanced stages in the lower 

 part, is exhibited. The stomach is enormous. (After Jullien, 18S8. ) 



est, stomach ; gt, tentacular sheath ; mr, retractor muscles of polypide ; r, rectum ; t, tentacles. 



Genus HIPPADENELLA Canu and Bassler, 1917. 



1917. Hippadenella CANU and BASSLEB, Synopsis American Early Tertiary Cheilostome 

 Bryozoa, Bulletin 96, United States National Museum, p. 54. 



The frontal is a pleurocyst surrounded by areolae. The apertura bears two 

 cardelles. The mandibles have a lucida in the middle. The avicularian chamber 

 shows a double gland-like body and the protoplasmic mass. 

 55899 19 Bull. 106 32 



