GRAPTOLITES OF NEW YORK, TART 2 



393 



pal criterion of distinction between the two species, we have preferred to 

 associate the present variety with G. quadrimucronatus. 



Glossograptus quadrimucronatus (I I. ill) var. cornutus nov. 



Plate 27, figures 8-io 



The rhabdosomes oi this variety are ol medium size (average length 



25 mm, rarely surpassing" 30 mm, and width 2.5-3 mm), beginning with a 

 rounded sicular extremity 1.2 mm 

 wide ; rapidly attaining the full 

 width (in space of about 4. mm). 

 Sicular extremity buttonlike and 

 furnished with two long, hornlike 

 curved lateral spines and a strong 

 virgfella, all of which show oreat 

 individual differences in develop- 

 ment. Nemacaulus very thin and 

 hairlike. Test thick. Sicula 2 

 mm long". Thecae numbering 10 

 to 1 2 in 10 mm ( 25-30 in space of 

 1 inch ), one third as wide as long, 

 inclined 30" to the axis, overlap- 

 ping one half their length. Aper- 

 ture rectangular to axis, broad and 

 slightly concave. Apertural spines 

 as long as aperture, straight, and 

 directed horizontally. 



-r 



338 



341 



Tnic v-inVrv Iti^ Kppn found Fi S- 338-42 Gloss ograp t u s quadrimucronatus var. 



iniS\dliet) liaS Deeil IOUllCl cor 6 nu r us nov. Fig. 338 Rhabdosome. Fig. 339 Portion of 



rhabdosome showing both apertural spines of thecae. Fig. 340 



onl\' at the Rural Cemetery near Sicular end,_ showing sicula, first : theca and large lateral spines. 



J J Fig. 341 Sicular extremity with three large spines. Fig. 342 



^ 11 1 ,1 ■ Growth stage of rhabdosome with three thecae. Figures ;;'■:, 139, 



Albany, bUt there HI great lllim- 3 4 iare enlarged x 5: figures 340, 342x7 



ber and excellent preservation. Its most striking features are the long 

 apertural spines and the strong, frequently curved lateral spines of the 

 sicular end, in support of which the test of that whole part has become so 

 much thickened that the extremity frequently stands out buttonlike. From 



