90 



BULLETIN 11, UNITED STATES NATIONAL MUSEUM. 



its most interesting characters are brought out in thin sections. In 

 tangential sections, the thick zocecial walls and the large, somewhat 

 imdefined hmarial thickening, are characters which would be expected 

 from a study of the surface. The roimded cyst-hke bodies seen in 

 zocecial tubes in vertical sections, are, however, most unexpected, 

 and are structures which are here noted for the first time in this 

 group of the ceramoporoid bryozoans. The significance of these 

 bodies and the bearing of this discovery upon the zoological position 

 of the whole group have been mentioned in the remarks under the 

 genus. I can only add here that their occurrence in the tubes as 

 well defined, rounded vesicles, distinct from the diaphragms and 

 attached at one side to the zocecial wall, is indicative of their physio- 

 logical importance. From comparison with recent species, they 



Fig. 28.— Ceepipora incrassata. a, edge yiew of the type-specimen, natural size; 6, tangential 



SECTION, X20, SHOWING THE THICK "WALLS AND OBSCURE LUNAEIUM; C, VERTICAL SECTION, XIO, CUTTING 

 TWO LAYERS OF ZOCECIA; d, PORTION OF A VERTICAL SECTION, X20, ILLUSTRATING OVICELL-LIKE BODIES 

 AND STRUCTURE OF WALLS. WasSALEM BEDS (D3), UXNORM, EsTHONIA. 



would seem to bear most resemblance to the ovicells of cyclostomatous 

 bryozoans. 



Vertical sections also show the porous, laminated wall structure 

 and the thin, delicate diaphragms occiu-ring in this genus. In the 

 present form the latter average their own diameter apart in the 

 mature portion. The massive zoarium, thick walled, polygonal 

 zocecia, large, indefinite lunarixmi, and, internally, the rounded 

 bodies occurring occasionally in the tubes, distinguish C. incrassata 

 from aU other species of the genus. 



Occurrence. — A single specimen was presented to the United States 

 National Museum by Dr. August von Mickwitz, who found it in the 

 Wassalem beds (D3) at Uxnorm, Esthonia. 



Eolotypc—Csit. No. 57200, U.S.N.M. 



British Museimi's collections contain a fragment of the type- 

 specimen and thin sections. 



