22 2 NEW YORK STATE MUSEUM 



stem and branches a very fine continuous ridge runs. The stem shows, at 

 intervals of about 1.5 mm, cross furrows which ma)' correspond to thecal 

 apertures. 



Horizon and locality. Utica slate, Turin, Lewis co., X. Y. (label on 

 type specimen in Am. Mus. of Nat. Hist., New York city). 



Through the kindness of Professor Whitfield the type specimen has 

 been loaned to the present writer for study and a much enlarged camera 

 drawing obtained [see pi. 12, fig. 6] which illustrates additional features. 

 The branch shows the same median line as observed in M . tenuira- 

 mosus and M. simplex and distinct circular pits, from 2 mm-2.5 mm 

 apart. The form is hence brought into association with the just mentioned 

 species under Mastigograptus. While we believe with Gurley that it is 

 different from these other species, its measurements (width of 4 mm and 

 distance of pits) are very close to those of M . simplex and it is very 

 closely related, at least, to that species, the fragmentary state of the type 

 precluding any positive conclusion. 



Mastigograptus circinalis sp. nov. 



Plate 10, figure 3 ; plate 12, figures 7, 8 



Dendrograptus sp. Ruedemann. N. Y. State Mus. Bui. 42. 1901. p. 528 



Description. Rhabdosome small, consisting of very thin (.2 mm) fili- 

 form, extremely flexuous stem and equally flexuous, still thinner alternating 

 branches dividing repeatedly into long branches of higher orders, the process 

 of subdivision continuing until almost invisible, long hairlike branches result. 

 Stems and branches possess a strong tendency to become, each independ- 

 ently, enrolled. Thecal apertures seen as fine circular pits numbering 9 to 

 11 in the space of 10 mm. 



Position and localities. Observed only in the Utica shale at the Rural 

 cemetery near Albany, in association with Glossograptus quadr i- 

 mucronatus var. corn ut us, G. (?) eu char is and Climaco- 

 g r a p t u s p u t i 1 1 u s. 



Remarks. In a paper on the Hudson River beds near Albany, the 

 writer has cited this form as Dendrograptus sp., commenting on its 

 points of similarity with T h a mnograptus c a p i 1 1 a r i s and M . ten- 



