Mr Lapworth on the Genus (Nemagraptus Nematolites). 107 



branches, round at the base and flattened at the extremities ; 

 cells appear to be arranged on the flattened part of the axis 

 instead of the margin." 



Two species of Nemagra'ptus are described and figured in 

 the "American Geology," * viz : Nemagra'ptus elegans and 

 Nemagraptus capillaris. 



The figure of Nemagraptus elegans shows a Graptolite-like 

 fossil with a slender arcuate stem of about half an inch in 

 length, giving off six simple, elegantly-curved, and very 

 slender branches at sub-equal distances along its convex 

 margin. According to Emmons's description, these branches 

 expand somewhat towards their distal extremities, but show 

 no trace whatever of marginal serrations. Under the micro- 

 scope the surface of the fossil is seen to be " slightly dotted, 

 so as to give the appearance of the mouth of cells." 



The second species, Nemagraptus cajnllaris, is a remark- 

 able thread-like form, with a main stem of about seven inches 

 in length, and of almost equal diameter throughout. It 

 appears to have been highly flexuous, and is irregularly coiled 

 up into a space of little more than a square inch. This main 

 stem throws off a few simple branches, apparently from both 

 margins, at distant and irregular intervals. These are capil- 

 lary and flexuous like the main stem, but do not exceed one- 

 fourth of an inch in length. 



In the first volume of the " Palseontology of New York," 

 issued in 1847, and about eight years previous to the publi- 

 cation of Emmons's "American Geology," Professor James 

 Hall had already described and figured numerous Graptolites 

 from the slaty rocks of the valley of the Hudson Pdver. 

 Among these, one,i" named by Hall Grap)tolitlius gracilis, bears 

 at first glance a striking general resemblance to Emmons's 

 Nemagraptus elegans, as figured in the "American Geology." 

 Accordingly, in 1865, we find HaU in his fine work on the 

 " Graptolites of the Quebec Group," very naturally claiming 

 Emmons's Nemagraptus elegans as " part of an individual of 



* Emmons : "American Geology," PI. i., figs. 6 and 7. 

 t Palseontology of Xew York, vol. i., PI. Ixxiv. 



