PLATE CIV. 



PAGE 



Figs. 1-6. Aulocystis zittelii, W. Marshall, . .361 



Fig. 1. A somewhat damaged specimen, preserved in alcohol ; natural size. 



Fig. 2. Macerated specimen with two oscular apertures ; natural size. 



Fig. 3. Transverse section of a tube-wall (combination figure); x 60. 



Fig. 4. Graphiohexaster with somewhat undulating terminal rays ; x 300. 



Fig. 5. Discohexaster with short principal rays ; x 300. 



Fig. 6. Discohexaster with long principal rays ; x 300. 



Fig. 7. Aulocystis grayi, Bowerbank, . . . 3.59 



Fig. 7. Discohexaster with short principal and numerous long terminal rays ; 

 x300. 



J 



