Art. III. — Notes on some Lancefield Graptolitcs. 

 By Gr. B. Pritchard. 



[Eead 8th March, 1894.] 



Ill the Proceedings of this Society for the year 1891, Mr. T. S. 

 Hall, M.A., described a new species of Dictyotiema under the 

 name of D. gratide. Since the publication of that paper I have 

 been fortunate enough to obtain among some additional examples 

 of the species, an exceptionally perfect and well-preserved speci- 

 men, with the hydrothecas well developed and clearly discernible. 

 Mr. G. Clark, who accompanied me on the occasion of obtaining 

 this prize, kindly drew my attention to a small exposure of the 

 free branches of the polyp-stock on a face of the outci-op, and by 

 exerting a little care I was able to secure both sides of a perfectly 

 entire specimen. I take this opportunity of thanking Mr. Clark 

 for his kindness in so readily handing over his right to this 

 specimen. 



Genus Dictvoxema, Hall. 



Dictyonema, thougli it has been very often placed among the 

 Graptolites, strictly speaking does not belong to them, as the 

 very characteristic chitinous supporting rod of that group is 

 absent. Professor Nicholson* regards Dictyonema as probably 

 an early type of the Order Thecaphora of which Sertiilaria and 

 Camparitilaria are living representatives. Zittelf appears to 

 hold the same view, as he places it in the Sub-order Campanu- 

 laricB. 



The genus was originally founded by Professor J. Hallj in the 

 following language : — " Fronds consisting of flabelliform or 

 funnel-shaped expansions (circular from compression), composed 

 of slender radiating branches, which frequently bifurcate as 

 they recede from the base. Branches and subdivisions united 

 laterally by fine transverse dissepiments ; exterior of branches 



* Manual of Palseontology, vol. i., p. 204. 



t Handbucli der Palaeontologie, Band I., p. 289. 



% PalEeontoIogy of New York, vol. ii , p. 174, 1852. 



