150 



Graptolites,* though Mr. Joseph F. James asserts that it is undoubtedly 

 a Dictyonema. t It seems to be a much larger species than /. a/rbuscula, 

 with branches apparently devoid of the " strong, prong-like projections 

 rising from the sides at variable intervals,'' which are said to characterize 

 that species, forming a more complete network, with very numerous; fine 

 meshes. Mr. Ulrich, to whom one of the best specimens from Inmost 

 Island was submitted, thinks that it is quite distinct from his /. arhuscula, 

 and that a new genus, near to Dictyonema, ought perhaps to be con- 

 stituted for the reception of these two species. In the absence of any 

 knowledge of the base of attachment of /. Canadensis, it is not at all clear 

 to the writer how it can be separated generically from Rhizograptus, 

 Spencer. 



ACTINOZOA. 



ALCYONARIA. 



Halysitbs catenularia, L., var. gkacilis. 



Catenipora gracilis. Hall 1851. In Foster & Whitney's Geol. Land 



Distr. Lake Superior, pt. 2, p. 212, pi. 



29, figs. 1, a-h. 

 Halysites catenularia, Whitesive.s 1880. Geol. Surv. Canada, Rep. Progr., 



1878-79, p. 45 c. 

 ,, ii It 1881. Geol. Surv. Canada, Rep. Progr., 



1879-80, p. 57 0. 



Original description of Catenipora gracilis : 



" Coral massive or hemispheric ; cells quadrangular or suboval ; walls 

 thin ; interspaces rarely thicker than the walls ; arranged in a single 

 series, in wide, irregular reticulations. 



"This species differs from the C escharoides in the almost quadrangular 

 form of the cells and the extremely thin walls, the reticulations are 

 wider and the whole aspect less solid than in that species. From C. 

 aggloraerata it differs essentially in the form and arrangement of the 

 cells. 



"This species occurs in the green shales near the upper part of the 

 Hudson River group, and so far as I know is the first time that a species 

 of this genus has been found in the Lower Silurian series. 



"Eastern shore of Green Bay, Wisconsin." 



Mr. L. M. Lambe, who has recently made a special study of Canadian 

 specimens of Halysites, thinks that Catenipora gracilis, Hall, is a strati- 

 graphic variety of Halysites catenularia, and characteristic of the 

 Galena-Trenton limestone of Lake Winnipeg and its vicinity, and of the 



*Journal of Geology, Chicago, vol. IV., 1896, p. 99. 



fJournal of the Cincinnati Society of Natural History, vol. XIV. (1891) p. 153. 



