96 BULLETIN OF THE LABOFv ATORIES 



Other species associated in this horizon await a better opportunity. 

 We reproduce part of Prof. Hall's description. " Zoarium consisting 

 of a flattened, dichotomously branching frond arising from a spread- 

 ing base. Branches 3-4 mm ; margins sometimes parallel, at others 

 slightly diverging, the greatest increase in width in a length of 15 

 mm. being i mm; non-celluliferous marginal space narrow, width .15 

 mm, not flat ; transverse section regularly convex on the two sides, 

 greatest thickness .50 mm; bifurcations comparatively distant, 

 branches diverging at an angle of 60° or more. Cells tubular, for the 

 greater portion of length very oblicpie, often nearly parallel to the 

 mesotheca, then turning and opening obliquely to the surface, on the 

 narrower portion of the branches often recumbent for nearly the en- 

 tire length. ^' * '^''. Cell apertures very broadly oval, 

 often circular, sometimes pustuliform, disposed in somewhat irregular 

 longitudinal rows, but the rows being very close together and the ap- 

 ertures being separated by more than twice their diameter, the ar- 

 rangement is indistinct ; they sometimes alternate and form oblique 

 transverse rows and often irregular, direct transverse rows. Marginal 

 apertures very little if at all larger than the others. Peristomes mod- 

 erately thick, strongly elevated, smooth; interapertural and marginal 

 space striated, striae short, tortuous, interrupted." 



While some doubt may still exist as to the identity of our species 

 with the above, its Devonian affinity is obvious. 



Addenda. 

 \7o Page 65. J 



Schizodas [Protoschizodits] palaeotielHforniis, ^P- "• 

 (Plate XII, Fig. 44.) 



Six specimens found since the above was [jrinted present concord- 

 ant characters. 



Of small size, sub-nuculiform, produced behind, equivalve, 

 length to height as 23 to 15. Beaks less than one-third the length from 

 th^ anterior; hinge somewhat over half to nearly two-thirds the total 

 length ; anterior margin short, broadly rounded, passing gently into the 

 very slightly and uniformly curving lower margin, which meets the 



