GRAPTOLITES OF NEW YORK, PART 2 



8 9 



of and strikingly resembles an elliptic pinnate-veined leaflet, a resemblance 

 hi<>-htened by the likeness of the virgula to the midrib, and the presence of 

 several obscure, obliquely directed fibers running from it on either side 

 outwards and proximalwards. An exactly similar but differently-shaped 

 appendage is constant in C. caelatus from Nevada, and probably it is 

 equally constant in C . p h y 1 1 o p h o r u s, though here 

 the longer, more slender virgula is more frequently broken. 

 This appendage appears to differ from that found in such 

 species as Diplograpsus vesiculosus Nicholson 

 in being accurately bilaterally symmetrical, and in being 

 plainly traversed by and not forming (as apparently is 

 the case in D . vesiculosus) a dilatation of the 



We copy here his figure in illustration of his views. 



In specimens of Climacograptus caelatus 

 from the Beekmantown shales at Summit, Nevada, Gurley 

 has also observed a dilatation of the nemacaulus of which 

 he says [1896, p. 76] : 



Fig. 20 C 1 i m a c o- 



This bodv is an obtrian^ulate-cordate leaflet, bilater- Han. khabdosome with 



, J . ° . T 1 i 1-1 dilatation. Copy from 



ally symmetrical, and traversed medianly by the virgula. Gurle >' 

 Some appearances suggest that it may possibly consist of two superposed 

 elliptic leaflets. It is sometimes at a distance from, sometimes close to, or 

 in actual contact with the proximal (" distal ") end of the polypary. From 

 the (apparent) dilatations of the virgula seen in D . vesiculosus 

 Nicholson, D. pal me us (Barrande) and D. trifidus Gurley, it 

 differs markedly in its distinct bilateral symmetry, and flat leaflike appear- 

 ance. This "disk" is present in a large proportion of the specimens. 



Gurley did not figure these 



disks in the preliminary publication 



from which this note is taken, but 



we have found in his manuscript 



some figures of the same made 



under his supervision, which are 



reproduced here [text fig. 21] ; and 



we add some camera drawings of 



our own to further illustrate certain features [text fig. 22]. 



A further form with a dilated nemacaulus was made known by Elles 



Fig. 21 Climacograptus 



caelatus Lapworth. Copies 

 of Gurley's figures showing the 

 "disk." x % 



Fig. 22 Climacograp- 

 tus caelatus Lapworth. 

 Camera enlargements of the 

 dilatations, x 5 



