BIBLIOGRAPHIC LIST OF GENERA AND SPECIES. 435 



Didymograptus sagitticaulis Continued. 



Didymograpeua convexus Gurley, Jour. Geol., 4, 1896, p. 67, pi. 5, fig. 8. 

 Didymograptus sagitticaulia Ruedemann, Mem. New York State Mus., 11, pt. 2- 



1908, pp. 248-251, pi. 14, fig. 3, text figs. 151-155. 

 Chazyan (Normanskill): Kenwood, Stockport, and near Poughkeepsie, New York; 



Canada; Arkansas (Stringtown); Tennessee (Athens). 



:otypS.~ Cat. No. 54255, U.S.N.M. (Gurley types of D. convexus.) 



Didymograptus serratulus (Hall). 



Graptolithus serratulus Hall, Pal. New York, 1, 1847, p. 274, pi. 74, fig. 5a, b. 



Chapman, Canadian Jour., n. s., 1, 1856, p. 390, text fig. 8 Hall, New York 



State Cab. Nat. Hist., 20th Rep., 1867, p. 223f. Walcott, Trans. Albany 



Inst., 10, 1883, p. 35 (adv. sheets, 1879). 

 ?Graptolithus (Monograptus) serratulus Whitfield, U. S. Geog. Surv., 100th Mer., 



Lieut. Wheeler's Rep., 4, 1877, p. 19. 

 Graptolithus (Monoprion) serratulus Hall, 20th Rep. New York State Cab. Nat. 



Hist., 1868, p. 226; rev. ed., 1870, p. 260. 

 Didymograptus serratulus Walcott, Geol. Soc. Arner.,Bull. 1, 1890, p. 338. Gurley, 



Geol. Surv. Arkansas, Ann. Rep., 3, 1892, p. 411. Roemer and Freeh, Leth. 



Pal., 1, 1897, p. 589. Ruedemann, Bull. New York State Mus., 42, 1901, pp. 



497, 541. Elles and Wood, Mon. British Grapt., pt. 1, 1901, p. 29, pi. 2, figs. 



7a, b, text fig. 18a-b. Ruedemann, Mem. New York State Mus., 11, pt. 2, 



1908, pp. 251-253, pi. 14, fig. 4, text figs. 156-159. 

 Didymograpsus serratulus Pictet, Traite de Pal., 2d ed., 4, 1857, p. 474, pi. 108, 



fig. 23. 



Middle Ordovician: Kenwood, Stockport, etc., New York; Arkansas (Normans- 

 kill); Great Britain (Glenkiln). 



Didymograptus serratulus juvenalis Ruedemann. 



Didymograptus serratulus juvenalis Ruedemann, Mem. New York State Mus., 11, 



pt. 2, 1908, p. 252, fig. 156. 

 Chazyan (Normanskill): Kenwood, New York. 



DIDYMOGRAPTUS SEXTANS Nicholson. See Dicellograptus sextans. 



Didymograptus similis (Hall). 



Graptolithus similis Hall, Geol. Surv. Canada, dec. 2, 1865, p. 78, pi. 2, figs. 1-5. 

 Didymograpsus similis Gurley, Jour. Geol., 4, 1896, p. 295 (gen. ref.). 

 Didymograptus similis Ruedemann, New York State Pal., Ann. Rep., 1902, pp. 



566, 567; Mem. New York State Mus., 7, pt. 1, 1904, pp. 677-679, pi. 14, 



figs. 25-29, text figs. 73, 74 (73 on p. 678). 

 Canadian: Point Levis, Quebec (Levis, Didymograptus zone); Deepkill, Rens- 



selaer County, New York (Deepkill, Didymograptus and Diplograptus zones); 



Wales (Arenig); Norway; Sweden. 



Didymograptus spinosus Ruedemann. 



Didymograptus spinosus Ruedemann, Mem. New York State Mus., 7, pt. 1, 1904, 



pp. 688, 689, pi. 14, figs. 30-32, text figs. 84, 85. 



Canadian (Deepkill, Diplograptus dentatus zone): Mount Moreno, Columbia 

 County, New York. 



Didymograptus subtenuis (Hall). 



Graptolithus tenuis (Portlock?) Hall, Pal. New York, 1, 1847, p. 272, pi. 74, figs. 



2a-d. 

 Graptolithus subtenuis Hall, in Miller's Amer. Pal. Foss., lated., 1877, p. 244. 



Walcott, Trans. Albany Inst., 1883, 10 (adv. sheets, p. 35). Gurley, Jour. 



Cincinnati Soc. Nat. Hist., 16, 1892, p. 156. 



