GRAPTOLITES OF NEW YORK, PART 1 



(JOT 



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are not very frequently bifurcating, the resulting branches forming 

 acute angle ; branches closely arranged, about 14 of them being counted in 

 10 mm ; separated by interspaces of equal width 

 mth the branches. Thecae acately dentiform, 

 disposed on one side of the branches ; number- 

 ing 16 in 10 mm; provided with a short, stout, 

 furcate apertural process, which embraces the 

 dorsal part of the next adjoining branch. 



Position and localities. Rare at the Deep 

 kill in graptolite bed 2 (Tetragraptus zone) and 

 graptolite bed 3 (zone mth Didymograptus 

 b if idus ). 



Remarks. Besides small fragments and 

 less favorably preserved branches there has 

 been observed the single larger specimen which 

 has been figured. This is specially noteworthy 

 on account of the pyritization of the thecae in 

 some parts [see enlarged text figure], whereby 

 the normal juxtaposition in the branch of sev- 

 eral (apparently three) slender tubes becomes 

 apparent. 



The character of the dissepiments, which 

 are prolongations of the thecae ending in 

 furcate processes connects this species with 



D. cavernosum and peltatum Wiman, from the Lower Siluric of Got- 

 land, and with D, cervicorne Holm, from the Upper Siluric of Gotland. 



m<.im 



k 



f 



Fig. 28 Dictyonema furclferum 

 sp. nov. The composite character of the 

 thecae is shown by a partial infiltration of 

 the component tubes with pyrite. Deep 

 kill, xr 



Dictyonema rectilineatum sp. nov. 



Plate 3, figure 10 



cf. Dictyonema delicatulum Dawson. Can. Nat. and Geol. 1883. 10:461f 

 Dictyonema sp. nov. Euedemann. N". Y. State Paleontol. An. Rep't. 1902. 

 p.570 



Description. Form of entire rhabdosome not known. Branches at 

 proximal end forming an irregular mesh work ; in a more distal zone radiat- 



