30 



BULLETIN 65, UNITED STATES NATIONAL MUSEUM. 



totally different species, the one I have named D. poJymorphum. It is vei'y 

 important to note that his description, too, has Ijeconie tinctured with foreign 

 elements, the whole of the second {paragraph, with the possible exception of the 

 statement that " between the branches there are not usually spaces as great as 

 (or greater than) their own width," having no application to the present species. 



Horizon and locality. — Not uncommon in the Niagara dolomite, 

 chert, and glaciated chert at Hamilton, Ontario. 



The originals of text figure 32 and Plate 2, figure 4, are in the 

 National Museum, while the third figured specimen (fig. 33) belongs 

 to the Spencer collection. 



Plesiotypes.—Qfii. No. 55300, U.S.N.M. 



DICTYONEMA STENACTINOTUM Gurley, new species. 



Plate 3, figure 2. 



Gurley's description of this fine new species follows : 



Polypary flabelliform, included within an angle of 35°, somewhat obscure 

 at base; branched 0.6-0.8 mm. wide (in places apparently as narrow as 0.4 mm., 



but they are there not fully 

 exposed, as the same 

 branches elsewhere show 

 in their course the full 

 width) ; mostly parallel, in 

 places curving irregularly, 

 causing distortion of the 

 meshworii ; set 17-18 in 25 

 mm. of width. Dissepi- 

 n)ents slender or thick, sev- 

 eral reaching O.G mm. and 

 but for their position being 

 virtually indistinguishable 

 from a nearly transverse 

 l)ranch. The majority are 

 transverse, though many are 

 more or less and some are 

 (piite oblique. Most are 

 ]iarallel-sided ; a number are 

 iriangular. In general the 

 meshwork is regular, the 

 meshes rectangular. The 

 most regular meshes vary in length between 1.5 and 2.5 mm. Distorted meshes 

 may be as short as 0.5 mm., though more usually 1 mm. is the minimum, (^idy 

 obscure indications of thecfe are seen. 



The above description refers to the type-specimen alone [flg. 34]. One other 

 specimen [text flg. 35, PI. 3, fig. 2], from approximatel.v the same liorizon, 

 exhibits a general i-esemblance to the type, but with some differences. It may 

 be described as follows: 



Polyjiary known only in the form of a fragment of tlie meshwork; branches 

 heavy (0.8 mm. wide), parallel, diverging only very slightly, bifurcating cor- 

 respondingly rarely (the few successive bifurcations visible are 12-20 mm. 

 apart) ; set 15 or 10 in 25 mm. of width. Dissepiments when unworn probably 



Figs. 34, 



SPECIES. 



35. — DiCTYONEMA STEN.\CTINOTUM, NEW 

 34, HOLOTYI'E. 35, A khabdosome re- 



FEURED SO.MEWHAT DOIBTFULLV. (SeE ALSO PL. 3. 



FIG. 2.) 



