DENDROID GRAPTOLITES OF HAMILTON, ONTARIO. 21 



overlies the base of the next cell, so that there are from 25 to 32 calycles in the 

 length of a centimeter. More frequently only circular, or ellipsoid, elevated 

 (sometimes depressed) points mark the former abodes of the polypites, which, 

 being surrounded by a denser texture, have not yielded to the pressure which 

 has flattened the walls of the common canal. The irregular strife and depres- 

 sions on the stipes and branches are probably occasioned by the unequal flatten- 

 ing of the canal and celluliferous portions of stipes. 



This species is the most easily obtained of the fossils of the group, though 

 good specimens are very uncommon. Generally we must identify them by the 

 relative size and arrangements of the branches and filaments, or, in more per- 

 fect specimens, by the form of the frond. 



Doctor Giirley described D. crassibasale as follows : 



Polypary, sometimes attaining a great size (one specimen indicates a diam- 

 eter for the whole polypary of nearly half a meter), usually, however, of more 



Fig. 23. — Dictyonema cijassibasale, new species. A co.mpressed ixfundibulifoem 



KHABDOSOME. 



moderate dimensions, cyathiform. consisting of parallel branches which radiate 

 almost straight outward, but which are slightly flexuous in portions of their 

 course. Their typical width is 0.5-0.6 mm. Some, however, especially distally, 

 are as narrow as 0.4, and a few of the basal branches reach 0.8 mm. The 

 branches are set 25-30 in 25 mm. of width, the number tending to reach the 

 lower figure proximally and the higher figure distally. Distally, also, especially 

 in fragments of large polyparies, the branches are sometimes as many as 35 in 

 25 mm., but not, I believe, except where distortion has occurred, perhaps from 

 the dissepiments being more delicate in the younger portions of the polypary, 

 or from greater post-mortem dissociation of the more flexible distal portion. 

 Distally, too, the branches not infrequently, even in a normal polypary, will be 

 seen to be quite tortuous and the meshes more irregular. Bifurcations occur 

 at irregular and increasingly longer intervals. They are U-shaped, their sides 

 often tending to bow outward and then to approach each other above. It is 



