GRAPTOLITES OF NEW YORK, PART 2 



309 



Dicellograptus sextans var. exilis Elles <\: Wood 

 Elles and Wood have separated from I), sextans a variety as 

 exilis which agrees with the typical form in all its characters, except that 

 it is far more slender, (being only about half as wide as the true sextan s) 

 and is found in the same horizon with the latter. We have like narrow 

 specimens in the collections from Glenmont and Mt Moreno. In these the 

 width remains the same throughout and the spines are longer than in the 

 typical form. The original of Hall's figure 3a, plate 74 [see enl. 231] 

 belongs to this group. 



On the other hand, a slab from Kenwood in the State Museum has 



Fig. 231 Dicellograptus sextans var. ex- 

 ilis Elies & Wood. Hall's type of plate 74, figure 

 3a (vol. 1) x 5 



Fig, 232 Dicellograptus sex- 

 tans var. tortus nov. Obverse view, 

 X 5 



been found to be covered with specimens showing an opposite rend of 

 development [see fig. 232]. In this variety, which we will designate as D. 

 sextans var. tortus, the branches begin narrow and attain rapidly 

 the maximal width of the true sextans or one still slightly greater. 

 The spines are reduced to blunt mucros. The peculiarly braided appear- 

 ance of the branches is due to the fact that they are seen obliquely and 

 exhibit the greater part of the dorsal side, where a row of circular pits indi- 

 cates the budding points of the thecae. This state of preservation is evi- 



