PLATE II. 



Catostoma OTTAW:iENSE. (pago 18.) 



Figure 1. Portion of the frondescent form of the zoariimi. Natural size. 



^' 1 a. Fragment of the ramose form of the same. (See also wood cut, 

 pago .) Natural size. 



" 1 h. Tangential section from a si)ecimcn not figured. Enlarged about 

 fifteen times. 



" 1 c. Tangential section, from the frondescent form (Fig. 1), showing the 

 interstitial tubes. Enlarged about fifteen times. 



'^ 1 d. Portion of 1 h enlarged about thirty times. 



" 1 e. Longitudinal section showing the peculiar tabulation of this species. 

 Enlarged about fifteen times, 



^^ 1 f. Portion of the preceding section, enlarged about thirty times. 

 nOMOTRYPA SIMILIS. (pagO 10.) 



Figure 2, Sub-cylindrical form of the zoarium of this si)ecies j 2 a. Com- 

 pressed form of the same. Both natural size. 



'^ 2 h. Tangential section, enlarged about fifteen times. 



" 2 c. Portion of the same section, enlarged about ninety times. 



" 2 c7. Longitudinal section, enlarged about fifteen times. 



