GRAPTOLITES OF NEW YORK, PART 2 



435 



Climacograptus bicornis T. S. Hall. Roy. Soc. Victoria Proc. 



v. iS, pt 1, p. 2 1 

 Climacograptus bicornis Ami. Geol. Sur. Can. Sum. Rep't, 



igo4. (1905) p. 1 2 

 Climacograptus bicornis T. S. Hall. Geol. Sur. Victoria Rec. 



1906. v. 1. pt 4, p. 275; pi. 34, fig. 8 

 C lima c g r a p t u s b i c mis Elles & Wood. Monogr. Brit. Grapt. 

 pt 5. 1906. P-I93I 194. fig- 126; pi. 26, fig. 8a-f 

 var. pelt if er Lapw. 1876 (p. 6; pi. 2, fig. 53); 1877, p. 139; pi. 6, 



fig. 38b 

 var. trident at us Lapw. 1876 (p. 6; pi. 2, fig. 52); 1877^.139; 



pi. 6, fig. 38c 

 var. tuberculatus Nich. 1869, p. 229; pi. 11, fig. 18; Lapw. 



1876, p. 6 

 var. longispina T. S. Hall. 1902. Geol. Sur. N. S. 

 "Wales Rec. v. 7, pt 2, p. 5, pi. 12, fig. 8, 9 



Description. Synrhabdosome not observed. Rhab- 

 dosome linear in the middle and antisicular portions; 

 attaining great length (10 cm and more);' gradually 

 widening from the sicular extremity to a width of 2.6 + 

 mm, attained in about 30 mm and maintained close to 

 the antisicular extremity. The former extremity is 

 always armed with two diverging lateral spines, which 

 grow from the first two thecae, and the viro-ella which 

 greatly varies in length. The sicula is 1 mm long, its 

 greater portion embedded. The thecae number 12 in 

 the sicular region and 7 in the mature part and overlap 

 about one third their length ; their proximal walls are 

 curved, the free distal wall straight and parallel to the 

 axis of the rhabdosome. The apertural margins are rig. 404, 4 o 5 ci 



. . . , , . ., , -.-t us bicornis Hall. Fig. 404 



horizontal, the apertural excavations wide (one third Portion of rhabdosome of typical 



1 ^ specimen. Fig. 405 Rhabdo- 



1. 1 r . 1 \ 1 , , • • 1 . 1 r . 1 . 1 some presenting semiscnlariform 



ength ot theca) and attaining in depth one fourth the view ^middle portion omitted). 



x 5. St'i' also text figures 12-17 



width of the rhabdosome in mature part, and one third a,id P lateA 

 in the earlier part. Nemacaulus not observed. 



