288 NEW YORK STATE MUSEUM 



increasing, however, at end of first theca to 240 ; branches combined in a 

 gentle, flexuous curve to their extremities, averaging in width about o 5 mm. 

 Thecae 30 or 32 in 25 mm; adnate to the coenosarcal canal, with straight 

 or very slightly convex margins and slightly inclined apertural edge. 



The affinities of this form are distinctly with S. pertenuis Lap- 

 worth and its associates, S. explanatus and S . nitidulus. From 

 all these, however, it differs in absence of secondary branches and in general 

 form of polypary. 



Horizon and locality. Lower Dicellograptus zone, Stockport, N. Y. 



Gurley remarks : 



To the above description I may add that some specimens indicate that 

 the primary branches give origin to secondary ones, probably from the 

 athecaphorous margin, 



No figures of this species have thus far been published ; nor were any 

 found accompanying Gurley's manuscript. I therefore insert here drawings 

 of those specimens which were found in the Stockport collection and labeled 

 as S t ep h a n o g r a p t u s exilis as the original figures of the species. 

 One of these [pi. 17, fig. 4] shows the proximal parts of the secondary 

 branches and having been marked for illustration is evidently the specimen 

 to which Gurley had reference in the before-quoted note. Another speci- 

 men from Stockport [pi. 17, fig. 7], which apparently had been overlooked 

 by Gurley, retains the secondary branches to a considerable length on both 

 sides. 



y 



203 



Fig. 20a, 203 Nera.ijraptus exilis (Lapworth). Fig. 202 Enlargement (x 5} of the type. Fig. 203 Proximal 

 part of another specimen from Stockport, also x 5 



Much more complete material of this interesting form has been fur- 

 nished us by the shales at Glenmont [see pi. 17, fig. 3, 5, 9]. This, as well 

 as some of the Stockport material, suggests the following supplementary 

 notes : 



