xxvi SYNOPSIS OF GENERA. 



tubes, and at irregular distances tubes which have the same manner of growth 

 OS the primary rachis; this mo<le of growth is continued indefinitely, the 

 fronds covering a comparatively large area. Cell tubes turning abruptly out- 

 wanl-at their distal extremities and opening in an aperture parallel with the 

 axis of the branch. 



Exiunple : Reptaria stotonifera, pi. Ixv, figs. 17-19. 



Hederella, Hall (Trans. Albany Institute, vol. x, p. 194. 1881). 

 [Type, Alecto ? Canadensis, Nicholson.] 



Zoarium parasitic, consisting of a filiform tubular axis, with opposite or 

 alternate lateral budding of simple tubular cells ; also of lateral extensions 

 continuing in the same manner of growth as the initial axis. 



Examples: Hederella cirrhosa, pi. l.xv, figs. 12, 13. 



Hederella Canadensis, pi. Ixv, figs. 1-8, 14 and IG ? 



Hernodia, Hall (Trans. Albany Institute, vol. x, p. 196. 1881). 



I Type, Hernodia humifusa. Hall.] 



Zoarium parasitic, consisting of tubular, annulated cells, enlarging to near the 

 aperture ; increasing by lateral gemmation, and the buds continue growth in 

 the same manner as the parent tube, so that comparatively large surfaces are 

 often covered. 



Example : Hernodia humifusa, pi. Ixv, figs. 20, 21. 



Botryllopora, Nicholson (Geological Magazine. April, 1874). 

 [Type, Botryllopora socialis, Nicholson.] 



Zoarium consisting of small discoid bodies, occurring singly or in groups, 

 connected by vesicular tissue, 'adherent to foreign bodies by their under surface. 

 Cells tubular, disposed in double, radiating rows, forming alternating ridges. 

 Intercellular space vesiculose. 



Example : Botryllopora socialis, pi. Ixiv, figs. 3, 4. 



NoTB. — The restricted number of {Mices for the forei^foiiig SynopsiR has made it neceaaary to give the 

 briefest powihle dcHcription in order to notii-e the entire uumlier of genera in the volume. Much, thei-e- 

 fore, haa tieen omitted, cf<]>ccially the coniparisons and inter-i'ehitions of the genera. 



