176 Thirty-second Report on the State Museum. 



Thamniscus Nysa, var. 



(PLATE XXII, FIGS. 31, 32. )| 



The specimen has a mode of growth similar to the preceding species. The 

 cell-apertures are somewhat smaller and not so closely arranged. 



Formation and locality. Lower Helderberg group, near Clarkesville, N. Y. 

 Thamniscus fruticella, n. sp. 



(PLATE XXII, FIG. 33.) 



The only specimen observed is a small branching fragment of a frond, which 

 has a very different mode of growth from the other species. The celluliferous 

 side has not yet been observed. 



Formation and locality. Lower Helderberg group, near Clarksville, N. Y. 

 Thamniscus? Cisseis, n. sp. 



(PLATE XXII, FIGS. 23-30.) 



Bryozoum ramose, solid, celluliferous on one side, striate on the other ; diam- 

 eter of stem one mm. ; branches numerous, equal in size to the main stem, and 

 branching frequently, expanding very slightly below bifurcations : non-cellulif- 

 erous side striated, striae fine, numerous ; cell apertures small, round or slightly 

 polygonal from mutual proximity, their diameter about .25 mm. ; generally four 

 in the width of a branch, alternating, inosculating, forming very oblique 'rows ; 

 sometimes at the angles having minute spines. 



Length of largest specimen seen, twenty -five mm. 



Formation and locality. Lower Helderberg group, near Clarksville, N. Y. 

 Fenestella , n. sp. 



(PLATE XVIII, FIGS. 21, 22.) 



Fenestella , n. sp. 



(PLATE XIX, FIG. 16.) 



