GRAPTOLITES OF NEW YORK, PART 2 



26; 



Syndyograptus pecten sp. nov. 



Plate 15, figures 5, 6 



Description. Rhabdosome of small size, consisting of two stipes from 

 which at regular intervals paired secondary branches (12 or more) are given 

 off. The former have a double curvature, the)- are at first gently convex 

 for a short distance, and then concave. The angle of divergence of the 

 convex part varies between 200 and 250 and is typically about 230 ; the 

 axil is wide and open. The stipes are narrow (.3 mm at origin) and of 

 nearly uniform width (.5 mm at distance of 25 mm). The secondary 

 branches are straight and ascending, the pairs slightly diverging. The first 

 pair on either side of the center originates from the second theca of each 

 stipe and they follow at intervals of about 2.5 mm or corresponding to 



Fig. 184, 185 Syndyograptus pecten sp. nov. Two of the type specimens. Fig. 184 Showing 

 the sicula. x 5 



every third theca of the stipe, and widen more rapidly than the latter, 

 attaining a width of .5 mm at a distance of 15 mm. The sicula is incon- 

 spicuous [see fig. 185]. Its length is about 1.2 mm; its slender virgella 

 protrudes from the apex of the rhabdosome. 



The relations of the primary thecae are obscure in the specimens ; the 

 first theca seems to bud from the middle of the sicula, to be rather short 

 and to diverge but a short distance from the sicula, while the second theca 

 grows horizontally for nearly its whole length. It has been seen to bear a 

 short apertural spine. The third and fourth thecae are so situated, that 

 probably two crossing canals passed the sicula. The thecae are slender 

 and narrow, about six times as long as wide; they number mostly 10 in 

 10 mm, increasing to 12 in the proximal region ; their overlap is one fourth 



