172 CONTRIBUTIONS TO CANADIAN PALAEONTOLOGY. 



margins, from the circumference of which the thin-edged septa converge 

 leaving a broad, flat, smooth surface, the central part of the uppermost tabu- 

 lum, exposed at the bottom, although occasionally the septa are continued 

 as carinations to the centre. A deep septal fossette occurs in the side of 

 the bottom of the cup. Internal structure consisting of a combined 

 tabulate and septate area, in breath equal to about one-half the diameter 

 of the corallum, with a peripheral vesicular zone surrounding it. Septa, 

 numbering from about one hundred to over one hundred and seventy in 

 individuals of different degrees of slenderness, of two orders, alternately 

 long and short, continuous vertically within the psendowall formed by 

 the innermost plates of the vesicular area, the primaries cutting through 

 the down-turned edges of the tabulae for some distance, but leaving the 

 broad, flat or concave central portion untouched ; in the vesicular 

 area their vertical continuity is broken and they pass outward as sharp 

 carinations on the calicular margins, their differentiation in size being 

 still well marked. Tabulae broad, flat, undulating or slightly concave at 

 the centre, bending downward when they meet the septa and passing 

 between them to the inner limit of the vesicular zone. The blister-like 

 plates of the outer area, large, directed upward and outward, supporting 

 the periodic calicular margins formed in the growth of the corallum. 

 Epitheca thin, complete, with longitudinal striations corresponding to the 

 number and position of the septa, and with fine transverse growth lines ; 

 in most specimens its decortication, to a greater or less extent, exposes 

 the large vesicles within, or as is frequently the case, the removal of the 

 outer area by weathering lays bare the surface of the more compact core- 

 like septo-tabulate inner zone. As in Acrophyllum Oneidaense, small 

 spinous processes occur on the surface near the basal extremity. 



Localities and formation. — Corniferous limestone of Ontario ; loose spec- 

 imens have also been collected by Mr. George Barnston on the Albany 

 River near Old Fort Henley and on the Moose River (Devonian). 



Genus Lonsdaleia, McCoy, 1849. 



Lonsdaleia, McCoy. 1849. Ann. and Mag. Nat. Hist., second series, vol. III., p. 10. 

 " Corallum fasciculate or astraeiform. Besides the external wall, there 

 is a second, accessory, internal one. Columella thick, formed of rolled 

 lamellae. Peripheral part of the corallites, included between the two 

 walls, filled with vesicular endotheca ; septa well developed, reaching to 

 the vicinity of the columella but not extending to the outer wall. 

 Carboniferous.'' (Zittel : Traite de Paleontologie.) 



Type species. — L. duplicatus, Martin, sp. 

 Range. — Carboniferous. 



