202 NEW YORK STATE MUSEUM 



Lockport. The State Museum has a good series of specimens from the 

 lower third of the Rochester shale at Middleport. At the latter locality it 

 is one of the common forms and associated with Dictyonema reti- 

 forme, D . g r a c i 1 e , D . poly m o r p h u m and Inocaulis p 1 u - 

 mulo s us. A close relative of this species (P. clintonensis)is here 

 described from shale accompanying the Clinton iron ore. 



Our Middleport collection permits us to give the following additional 

 •data : 



The rhabdosome, when compressed vertically, assumes the form of a 

 circle, being about 10+ cm in diameter; originally it was infundibuliform 

 or cyathiform. In its lower part the wall of the cup or funnel was formed 

 by an approximately regular desitiograptoid reticulation, toward the margin 

 the branches became more bushy and left the surface of the cup as is shown 

 by the frequent overlapping of branches and along the growing margin 

 numerous bispicate extremities are seen. 



The thickness of the branches varies from .6 mm to i.8 mm and may 

 be said to be typically a little more than i mm ; the meshes are long 

 elliptic, numbering three to five, mostly four, in the space of io mm trans- 

 versely and vary in length from 3-8 mm, being typically about 5 mm long. 

 The branches are mostly reduced to a smooth, structureless film, but in 

 some portions the fibrous structure resulting from the composition of 

 tubular thecae is distinctly seen. Their margins are smooth and the thecal 

 apertures hardly, or not at all, projecting. 



Dr Ringueberg expresses some hesitancy in placing his species in 

 Inocaulis giving the character of the branches as his reason for referring it 

 to that genus and the reticulations or anastomoses as a differing character. 

 We have discussed the relations of Inocaulis to other genera before 

 arguing there that by reference to the genotype I. plumulosus only 

 forms with distinct projecting bundles of thecae along the margins, could 

 be properly referred to that genus. P. an as t o m o.t i ca has, however, 

 quite probably the normal thecae of a Dictyonema. We might add that the 

 nearest form to this in general appearance is a Siluric species i^' Bohemia 

 that has also been referred to Desmograptus and not to Inocaulis by PoCta 



