GRAPTOLITES OF NEW YORK, PART 2 



Dictyonema obovatum Gurley 



'5" 



Dictyonema obovatum Gurley. Geol. Sur. Ark. Rep't. 1S90. 1892. 3:418 

 Dictyonema obovatum Gurley. Jour. Geol. 1896. 4:300 



We have been unable to find the type of this species, in the collection 

 of the National Museum from the Lower Dicellograptus zone of the type 

 locality " near Crystal Springs, Arkansas." The species avowedly is based 

 upon but one specimen and this has been described but not yet figured. 



Dictyonema spiniferum sp. nov. 



Plate 1, figure 4 



Description. Entire rhabdosome not observed. Fragments of rhabdo- 

 sorae (40 mm long) consisting of subparaHel, straight or but slightly irregu- 

 larly bending branches ; .3—4 mm wide and separated by an interval that is 

 not at all or but little greater. Dissepiments frequent 

 and stout, forming with the branches rectangular 

 meshes, mostly 3 mm long. The thecae are promi- 

 nent, inclined at 30" and number 14 in 10 mm ; their 

 apertures are normal, and furnished with a very acute, 

 horizontal spine about as long as the aperture. 



Position and locality. Of this species but three 

 specimens have been collected in the Normanskill 

 shale at Glenmont, near Albany ; each in other 



56 Enlargement of fragment of 



association, viz, with Dicellograptus g u r 1 e y i, S , some showing form of 



' O 1 o J 1 mesnes. x 5 



Diplograptus foliaceus and D . a n g u s t i f o 1 i u s. 



Remarks. From the associated dendroid graptolites this form is 

 readily distinguished by its close meshwork and the prominence and dis- 

 tinct spinosity of the thecae. In the form of the thecae and its general 

 habitus it recalls D. furciferu m, a Beekmantown shale graptolite. 



Dictyonema arbuscula (Ulrich) 

 Dictyonema i r r e g u 1 ar e (Hall) James. The Palaeontologist. 1879 

 Inocaulis arbuscula Ulrich. Cin. Soc. Nat. Hist. Jour. 1879. 2:28, pi. 7, fig. 



27, 27a 

 Die t y ograp t u s reticulatus [tiomen nudum) Ulrich. Cat, Foss. Cincinnati group. 



1880. p. 61 



P'S- 55, 56 Dictyonema 

 spiniferum sp. nov. Fig. 55 

 Enlargement of branch showing 

 the thecae in profile view. Fig. 



