222 The Ottawa Naturalist. [February 



be made out sufficiently clearly to give the following data : — 

 Corallum astrajiform, made up of polygonal corallites from 3 to 

 7 mm. in diameter with deep calyces that join each other in 

 sharp-edged outlines and that have steep sloping sides and a 

 rounded boss, roughly 2 mm, in breadth, at the bottom. Each 

 corallite is contained within its own walls from which spring 

 lamellar vertical septa whose free edges are moderately con- 

 spicuous in the calyces. Septa, numbering from about thirty to 

 forty, alternately long and short, the former continued to the 

 centre where they are twisted, the latter about one-half or slightly 

 more than one-half the length of the former. Dissepiments 

 convex, arching evenly upward and outward and filling the 

 interscptal loculi in a circumferential area whose breadth is 

 equal to the length of the secondary septa or about one-fourth 

 the diameter of the corallite. Within the outer area is a zone 

 of dissepiments or vesicles that rise upward toward the centre 

 and in combination with the proximal ends of the primary septa 

 form a subvesicular mass that appears at the bottom of the calyx 

 as a rounded projection. 



The presence of continuous vertical septa such as the 

 above in corallites that are enclosed by definite walls makes 

 clear the necessity of removing the species represented by this 

 specimen from the genus AracJinopJiylluin ( Stroriibodes) ; 

 although some details of structure are obscured by crystallization 

 yet sufficient characters are preserved to suggest affinities to 

 Acervularia to which genus this species is for the present at 

 least assigned. 



Locality mid formation. — Manitouwaning, Grand Manitoulin 

 Island, Lake Huron, collected by A. Murray ; Niagara formation 



ChONOPHYLLUM Canadense, Billings, sp. 



PtychopJiylliim Canadense, Billings. 1862. Palaeoz. Fossils, vol. I, 

 p. 107. 



" Canadense, Billings. 1866. Cat. Silurian Fossils of 



Anticosti, p. 34. 



