GRAPTOLITES OF NEW ViiKK. PART 2 



2 59 



Nicholson [Ann. & Mag. Nat. Hist. 1873, M : ] 4 2 ] w * tn which they have a 

 considerable external resemblance and are also roughly contemporaneous. 

 But on further stud)' the fact that Lapworth cites the latter among the 

 crustaceans [1876, p. 7 ; 1877 expl. of pi. 7], while our form is undoubtedly a 

 graptolite, and that both authors here; mentioned figure the Scottish species 

 throughout with an abruptly set-off proximal mucro and a jagged, broken- 

 off distal margin, while the form here described has normally a regularly 

 expanding body and only under abnormal conditions exhibits the other 

 shape and also has a straight, smooth aperture, do not warrant any further 

 identification of the Normanskill and Scottish species [see text fig. 171]. 



Our material of A. ? simplex furnishes the following descriptive 

 data : 



Description. Rhabdosome consisting of large, broad sicula (dimen- 

 sions : length 5 mm; width 1.4 mm) 

 with straight, transverse apertural 

 marpfin and one theca which orisd- 

 nates near the middle of the sicula 

 and growing forward adheres to the 

 sicula as far as the latter's aperture, 

 then diverging slightly from the 

 direction of the sicula. The theca is 

 tubular, of about the same dimen- 

 sions as the sicula and also lacking- 

 apertural processes. 



Pntit-inw /?;;// JnmJitJe? Tfli<= Fig. 163-70 Azygograp t us ? simplex sp.nov. Fig. 



JrOi>1li01l ana tOCatZLieS, I HIS 163-05 Siculae. Fig. 166-68 Rhabdosomes. Fig. 169, 170 



Specimens which burst open x 3. Fig. 171 Dawsonia 

 SpecieS haS been Observed by the campanula* a. Nicholson. (Copies from Lapworth) 



writer in the Normanskill shales at Kenwood, Glenmont, Mt Moreno and 

 Lansingburg. It is most common at Mt Moreno, but best preserved at 

 Kenwood and Lansinpfburgf. 



Remarks. It should be noted that the form of the bodies here described 

 is subject to some variation, obviously due to conditions of preservation. 

 Some specimens may, e. g. assume a shape somewhat similar to D. cam- 



