OJ, 



GRAPTOLITES 01" NEW YORK, PART 2 



Dicranograptus furcatus var. exilis nov. 



Plate ; ;, figure 8 



In the Normanskill shale at Kenwood a variety is found whose 

 branches arc barely half as wide as those of the typical form (their width 

 =.5-6 mm). It thereby presents a much differing- aspect. Since the thecae 

 are not more closely arranged (they number 12 in 10 mm), they must be 

 relatively longer and narrower. Also the mesial spines are considerably 

 finer and hardly noticeable. No other differences have been observed and 

 the variety seems to be very rare. 



Dicranograptus contortus sp. nov. 



Plate 23, figure 9 



Description. Rhabdosome very small, in the contorted condition but 

 7 mm long, but the length of a branch was traced to 21 mm; consisting of 



273 



Fig. 277-74 Dicrano. 

 g rap t us furcatus 



var. exilis nov. En- Fig. 275-78 Dicranograptus contortus sp. nov. Fig. 275, 276 Enlargements 



largements (x 5) of bi- (x 5) of typical rhabdosomes. Fig. 277 Biserial portion of a specimen showing the form of 

 serial and uniserial por- the thecae. Fig. 278 The most frequent aspect of the branches, x 5 

 tions of specimen from 

 Kenwood, N. Y. 



a short biserial portion, which is 3 mm long and .8 mm wide, and contains 

 five thecae on either side and of relatively thick, uniserial, uniformly wide 

 (.7 mm) branches which in the compressed specimens are intricately con- 

 torted. The sicular extremity is rounded, furnished with long virgella and 

 conspicuous lateral spines. The sicula has not been observed. The thecae 

 are short and wide, very closely arranged, numbering 18 to 20 in the space 

 of 10 mm; overlapping apparently one third of their length; the ventral 



