5 9 6 



NEW YORK STATE MUSEUM 



tected by two [see "Remarks"] straight, rigid mucros (.8—1 mm long"), 



which arc- horizontal or slightly ascending in direction. 



Position and localities. This species is here found only in the Nor- 



manskill shale, at the Normanskill, Glenmont, Stockport and other localities. 



It is recorded from the rocks of the same age in Canada, hut not from the 



next zone. Gurley has also recognized it in the graptolite fauna of Arkansas, 



which is also of Normanskill a^e. In Great Britain it is a Glenkiln form. 

 Remarks. There is reasonable doubt as to the generic position of this 



species. Freeh has cited G. whitfieldi as the typical form of the 



spinose subdivision of Diplograptus, into which he 

 would incorporate the genus Glossograptus, holding 

 that the latter is based on fibrous appendages which 

 are not suitable for generic distinction. We have 

 seen, however, that other more important structural 

 differences from Diplograptus s. str. are combined 

 with the spinosity. In G . q u ad r i m u c r o n at u s 

 these have been observed in macerated specimens. 

 In the present species, which in its general aspect is 

 still more similar to Diplograptus than q u a d r 1 m u - 

 iL cr on at us, the lateral row of spines characteristic 

 of typical Glossograpti has not been observed, but 

 also in G. quadrimucronatus it occurs but 

 in rudimentary condition and in but one mutation. 

 Fig. 344, 34s Giossograp- On the other hand there is on the opposite side of 



tus whitfieldi (Hall). Fig 



344 Copy of original figure. 



bearing the typ< 



G 



whitfieldi a 



344 Copy ut original ngure. ,1 ^ -PiK 

 Fig. )45 Portion of type speci- Llie SlcllJ 

 men (in Ainer. Mus. Nat. Hist.). 



*s specimen that shows well the apertural and lateral 



ledo-es characteristic of th'j Retiolitidae, and a comparison oi the enlarge- 

 ment of the type specimen, here given in figure 345, with the drawings of 

 G. quadrimucronatus will readily show the identity of the aspects. 

 Subhorizontal spines are seen at the right corners of the apertures on o\w 

 side, and at the left corners on the opposite side. It is, hence, proper to 

 infer that the aperture was furnished with two spines in positions like those 



