612 



NEW YORK STATE MUSEUM 



50mm. Branches thin (.1mm), very closely arranged, numbering 16 to 20 

 in 10 mm, subparallel, undulating and coalescing at the 

 contact points, forming elongate meshes, eight of Avhich 

 have a length of 10 mm. True dissepiments occurring but 

 rarely. Thecal apertures not prominent, appressed, appear- 

 ing as closely arranged circular pores. 



Position and localities. Very common in graptolite 

 bed 7 of the Deep kill section, belonging to the horizon 

 with Diplograptus dentatus. 



RemarTcs. This species is readily distinguished by the 

 delicacy of its structure and the small size of its meshes 

 from D. cancellatus, which occurs in the same bed, 

 and by the undulating character of its branches from 

 Dictyonema rectilineatum, a similarly fine 

 meshed form of the same horizon. 



Fig.33 Desmogrrap- 

 tusintricatus. En- 

 larKeraent of portion of 

 the specimen reproducer! 

 on pl.3, fig.l. x8 



\ 



Order 2 graptoloidea Lapworth 



Suborder A graptoloidea axonolipa Freeh, em. Rued. 



Family dichogra.pxida.e: auct. em. Freeh 



sTAUROGRAPTUs Emmous 



(= CleraatograptQS Hopkinson and Clonograptiis Hall in parfi 



Emmons proposed, in the second part of his American Geology 

 [1855, p.l08] the new genus Staurograptus for a minute form, which he 

 had found in the " Taconic shales of Rensselaer county, N. Y." His defini- 

 tion of the genus is : " Disk free, cruciform, arms four, dichotomous cells 

 teiTninal, substance membranaceous, free and furnished with an axis." This 

 genus has, on account of the peculiar aspect, the cruciform division in the 

 center and the peculiarly broad dichotomous appendages \see Ermnons's two 

 drawings, reproduced here] of the genotype, S. dichotomus, been con- 

 sidered as doubtful at the beginning and later suffered still worse fate, for it 

 has in all newer works on graptolites been delivered to complete oblivion. 



