GRAPTOLITES OF NEW YORK, PART 2 1 63 



This species was found in the Niagara limestone [principally in the 

 shaly dolomite beneath the chert bed, 1884], Hamilton, Ontario, by Colonel 



Grant. 



Gurley adds the following - data to Spencer's description : 



Measurements of a number of branches show that these nearly all fall 

 between 0.4 mm and 0.6 mm, 0.4-0.5 being the dimensions usual in the 

 distal portion for the branches exclusive of the terminal twigs. The more 

 proximal stems measure 0.6 mm, and the thickest seen (in one specimen 

 only) reached 0.8 mm. Corresponding to the straggling aspect of this 

 species almost any number of branches may be counted transversely, but if 

 portions be selected where the branches are at fairly regular distances apart 

 and the meshes consequently of pretty uniform width, the number will be 

 found to be about 25 (say 23-27). 



Remarks. C . subretiformis is so well distinguished by its " strag- 

 gling aspect " that it can not be easily confounded with any other form. 

 The meshwork in Spencer's figure is distinctly coarser than that in any of 

 our specimens, but as the latter agrees in its dimensions with those given 

 by Gurley for C . subretiformis, the difference can be but small. 



One of our specimens, a young colony, retains the base in the form of 

 a thin, short (3 mm) stem and of an adhesion disk, a little more than 2 mm 

 wide. The form of the rhabdosome was very broadly infundibuliform. 



The thecae have not been seen. 



Spencer has erected the genus Calyptograptus for several species of 

 the Niagaran of Hamilton, Ontario, which are principally distinguished 

 from the similar genera, notably Dictyonema and Callograptus, by the 

 absence of transverse dissepiments. In the first diagnosis it is stated that 

 " in appearance and texture this genus resembles Dictyonema, but the 

 branches are [apparently] all independent, not being connected by trans- 

 verse dissepiments as in that genus and are only united in one mass at the 

 root," [although some of the branches touching each other have occasion- 

 ally all the appearance of connecting filaments]. This statement has later 

 (1884) been qualified by the same author by the additions here placed in 

 brackets, both of which tend to admit the occasional presence of dissepi- 

 ments. The absence of the dissepiments and the independence of the 



