LAMBE. 



CANADIAN PALEOZOIC CORALS. 117 



The writer is inclined to believe that the species Heterophrentis spatiosa* 

 Billings, is founded on short and unusually widely expanding specimens 

 of S. prolificum. The two type specimens are from Rama's Farm, Port 

 Colborne, Ont. Mr. Billings was doubtful as to the validity of the species 

 and concluded the original description with the remark that it is " closely 

 related to Z. prolifica, and may perhaps be united with it when its 

 characters become more fully known." 



Streptelasma rectum, Hall. 

 Plate VII., fig. 5. 



Strombodes ? rectus, Hall. 1843. Geol. of New York, p. 210, fig. 5. 



Cyathophyllnm rectum, Milne-Edwards and Haiine. 1851. Polyp. Fosd., des Terr. 



Palseoz. p. 372. 

 Streptelasma recta, Hall. 1876. Illus. Dev. Foss., pi. XIX., figs. 1—13. 

 Streptelasma rectum, Whiteaves. 1891. Contr. to Canad. Paheon., vol. I., pt. III., p. 

 199, pi. XXVII., figs. 1, la, and 2. 



The specimens that have been identified as representing this species in 

 Canada were collected on the Mackenzie River, 10 miles below Bear 

 River, by R. G. McConnell, in 1888. 



The Canadian specimens may be described as follows. — Corallum 

 simple, conical, straight or only slightly curved, pointed at the base, 

 reaching a length of 38 mm. with a maximum breadth of 15 mm. Outer 

 surface rather smooth with indistinct transverse accretion ridges and 

 minor lines of growth, and pinnately arranged longitudinal septal fur- 

 rows ; epitheca complete. Calyx exceeding in depth one half the height 

 of the corallum, its enclosing wall thin and steep, the floor consisting of 

 an exsert mass formed of dissepiments and primary septal ends. Septa 

 stout, alternately long and short, the primaries generally uniting in twos 

 or threes near the centre, secondaries almost obsolete; numbering alto- 

 gether in different sized specimens from about seventy to one hundred 

 and ten. In the calyx the primaries extend over the floor to the centre, 

 but on the sides they are much reduced in size and project only about 

 1-5 mm. inward from the wall ; free edges of the septa strongly toothed, 

 the denticulations being represented on the sides of the septa as slight 

 linear thickenings of the septa directed outward toward the wall. Dissepi- 

 ments irregular, small, occupying the narrow interseptal loculi, inclined 

 obliquely and convexly inward toward tho centre. 



Formation. — Devonian (Cuboides zone). 



* Described as Zaphrentis spatiosa in 1858 in the Report of Progress for 1857, and later 

 in 1874 in the Canadian Naturalist, new series, vol. VII, p. 235 under the name Het- 

 erophrentis spatiosa. 



