GRAPTOLITES OF NEW YORK, PART 2 395 



Diplograptus whitfieldi Nicholson. Monogr. Brit. Grapt. 1872. p. 54, 



fig- 2 3'> P- 6 9> fig' 39b 

 Diplograptus whitfieldi Lapworth. Cat. "West. Scott. Foss. 1876. pi. 2, 



fig- 45 

 Diplograptus w h i t £ i e 1 d i Lapworth. Belfast Field Club. An. Rep'1 & Proc. 



Ser. 2, apx. 1877. a-, i, pt 4, p. 134; pi. 6, rig. 21 

 Diplograptus whitfieldi Walcott. Alb. Inst. Trans. v. 10. 1883. 



(Advance sheet. 1879. p. 35) 

 Diplograptus whitfieldi Lapworth. Ann. & Mag. Nat. Hist. Ser. 5. 1880. 



6:21 

 Diplograptus whitfieldi Lapworth. Roy. Soc. Can. Proc. & Trans. 1886. 



4:184 

 Diplograptus whitfieldi Ami. Geol. Sur. Can. Rep't. Ser. 2. 1889. 



v. 3, pt 2, P.117K 

 Diplograptus whitfieldi Geinitz. Mitth. K. Min. Geol. praeh. Mus. Dres- 

 den. 1890. 9:35; pi. A, fig. 52 

 Diplograptus whitfieldi Gurley. Geol. Sur. Ark. Rep't. 1890. 3 141 1 

 Diplograptus whitfieldi Walcott. Geol. Soc. Am. Bui. 1890. 1 1339 

 Diplograptus whitfieldi Gurley. Jour. Geol. 1896. 4:298 

 Diplograptus whitfieldi Freeh. Lethaea Pal. 1897. 1:631; non fig. -192 

 Diplograptus whitfieldi Ruedemann. N. Y. State Mus. Bui. 42. 1901. 



P-497. 54i 

 Diplograptus whitfieldi Fearnsidos. Section C. No. 6. Belfast. 1902. 

 (separatum) 



Description. Synrhabdosome not observed. Rhabdosome of medium 

 size (attaining- a length of 35+ mm), beginning with a width of .8 mm, 

 gradually (within 10 mm) increasing to the full width, which is 2 to 3 mm; 

 thence parallel margined or slightly diminishing towards the antisicular 

 extremity, which is truncate. Nemacaulus thin, .1 mm wide; its free end 

 projecting sometimes to a length equal to that of the rhabdosome. Sicula 

 not observed. Sicular extremity furnished with a little conspicuous virgella 

 and two short lateral spines. Thecae numbering 9 to 11, mostly 10 in 10 

 mm (22-28 in 1 inch), inclined at an angle of about 30 . Three times as 

 long as wide, overlapping one half their length ; ventral and apertural mar- 

 gins straight, the latter normal to the axis of the thecae. Aperture pro- 



