GRAPTOLITES OF NEW VTORK, PART 2 289 



The main stipes describe, in the compressed state, a flat S-shaped 

 curve like those oi X. gracilis, one hall being ascending and the other 



descending" and the secondary branches being turned to opposite sides; the 

 latter begin at a distance of no less than 4 mm from the sicula, but are 

 mostly found in much greater distance (twice and thrice that mentioned) ; 

 the) - are 1.5 to 2 mm apart and attain considerable length (45+ mm), but 

 are very flaccid in appearance. There have been counted five to eight of 

 them on either side (in one case [pi. 17, fig. 7] apparently 12). They attain 

 a width of .4 mm. The sicula is very conspicuous on account of the absence 

 of branches near the center, and nearly always observable, though but 1 mm 

 long. It is furnished with a long rigid apertural spine. The two primary 

 thecae originate near the middle of the sicula and diverge a little farther 

 down in horizontal direction. They bear distinct, curved spines near the 

 aperture. The following thecae (stolonal or stem thecae) are slender, over- 

 lapping but one fifth their length and number 5 to 8 in 10 mm, while those 

 of the branches overlap one fourth and number 8 to 10 in 10 mm. They 

 are about five times as long as wide, their outer margin is gently convex 

 and the apertural part slightly, but distinctly introverted. 



From the habit of the complete Glenmont specimens and the dimen- 

 sions of the branches, the sicula and thecae we have little doubt but that this 

 form should be properly regarded as a variety of N. gracilis and that 

 it is nearer related to the var. remotus than to any other type of Nema- 

 graptus. In fact, we had identified our material with that variety until we 

 found that Gurley had designated like specimens as Stephanograptus 

 e x i 1 i s. It would seem that our variety agrees fully with that British 

 Glenkiln form in the curvature of the main stipes and the character and 

 dimensions of the thecae, but grows to greater size and develops more 

 secondary branches. An apertural spine of the sicula is not mentioned 

 of N. remotus in the Monograph of British Graptolites, but since 

 we have observed it in N. gracilis var. surcularis as well as in 

 numerous specimens of e x i 1 i s, we infer that it is a common feature of 

 several varieties, not well shown in the British specimens. 



