GRAPTOLITES OF NEW .YORK. I'AllT 1 



625 



Goniograptus perflexilis sp. nov. 



Plate 6, figures 16-18; plate 7, figures 1-9 



Goniograptus sp. nov. Ruedemaan. N. Y. State Paleontol. An. Rep't. 1902. 

 p.556 



In the t^vo lowest graptolite horizons of the Deep kill section occur 

 two closely allied species of very delicate raultiramous dichograptids which 

 unite the mode of branching characteristic of Goniograptus with the 

 diverging of the primary thecae from a point close to the apical end of the 

 sicula, peculiar to the coenograptids. The type occurring in the Tetragraptus 

 horizon is the one described here. 



Fig. 39 Goniograptus perflexilis sp. nov. :« Sicula and first theca. 7x;i; Growth stage of 

 rhabdosome with two first thecae. Obverse view. x7; c Similar stage. Kevei-se view. x7 ; rt Further 

 enlargement of proximal parts of first two thecae. x21. Deep Icill 



Description. Sicula extremely long and slendei' (4 mm long and but 

 . 3 mm wide), the first thecae originating close to the apical point of the sicula 

 [fig.39], and adhering to the latter for a very short distance and then pro- 

 ducing a second theca ; both first and second thecae diverging fi-om the 

 sicula at right angles ; these thecae but little shorter than the sicula and 

 equally narro\v, straight or slightly cui'ved, \vith the convex side directed 

 downward ; each of these thecae producing again two thecae, ^vhich together 

 form an angle of 80°. The resulting thecae form the bases of the four 

 principal stems, which, hence, diverge at an angle of 80° and Avhich, 

 as in the type species of the genus, give off undivided branches alternately 

 on opposite sides from the outer points of the angles of their zigzag 

 shaped course. The stem divisions form an angle of 160° with each 



