592 



Report of the State Geologist. 



Hemiphragma, Ulrich. 



(Report of the Geological and E^at. Hist. Survey. Minn., p. 



299. 1893.) 

 " Zoaria like Batostoma save in this, that the diaphragms in the 

 peripheral part of the zooecial tubes are incomplete." Ulrich. 



190 



■^^y 



191 



^.^M^^'^ 





192 



193 



Fig. 190. Hemiphragma irrasum. Specimens, natural size. 



Fig. 191. Surface, x9. 



Fig. 192. Vertical section, x9. 



Fig. 193. Cell walls, x85. 



Family Botrylloporidae, Miller. 



BOTRYLLOPORA, NicholsOU. 



(Geol. Mag. K S., Yol. I, p. 160. 1874.) . 

 Type, Botryllopora socialis, l^icholson. 

 (Plate 20, figs. 16, 17.) 



Zoarium consisting of small discoidal bodies, occurring singly 

 or in groups, connected by vesicular tissue ; adherent to foreign 



