184 CONTRIBUTIONS TO CANADIAN PALAEONTOLOGY. 



orders, alternating with each other within the pit, the primaries reaching 

 the centre or leaving a narrow, circular, smooth spot at the centre, the 

 secondaries not continued beyond the sides of the pit. As in A. pentagon- 

 um, Goldfuss, a coalescence of the inner septal ends in sets of twos, and 

 their continua.nce as single septa is often observed. Double rows of pore- 

 openings are present in the septal ridges. The dissepimental and vesicu- 

 lar structure is similar to that of A. pentagonum, only proportionately 

 smaller. Small flat tabute occur in the centre of the visceral chamber." 

 (Lambe, 1899.) 



Localities. — Five miles west of Chicotte River, Anticosti, J. Richard- 

 son, 1 856, division I V"., Anticosti group. Owen Sound, Ont., J. Townsend, 

 1874 to 1883; north end of Lake Temiscaming, Que., R. Bell, 1887: 

 Niagara formation. 



Aeachnophyllum eximium, Billings. (Sp.) 

 Plate XVI., figs. 3, 3a and 4. 



Strombodes eximius, Billings. 1866. Cat. Sil. Foss. of Anticosti, p. 93. 

 Arachnophyllum eximium, Lambe. 1899. Ottawa Naturalist, vol. XII., p. 245. 



" Original description. — ' Corallum composite, apparently forming large 

 depressed hemispherical colonies. Corallites from 9 to 15 lines across, 

 the calice slightly concave in the outer half of the width, the central 

 depression 3 or 4 lines wide. There are about fifty septo-costal 

 radii in a corallite 14 lines across. This species difiers from Strombodes 

 pentagonus and Strombodes striatus (both of which occur in the same beds) 

 in having much coarser radii.' 



" Additional specimens were collected by J. Townsend on Grand 

 Manitoulin Island in 1883 ; one specimen in particular shows the structure 

 admirably. 



" Further details as to the growth of the corallum are here appended: — 

 Corallum composite, explanate, discoidal, sometimes over 13 cent, broad 

 and 3 cent, thick, upper surface flat or slightly convex. Corallites upright, 

 confluent, varying in breadth from 2 to 3 cent., with shallowly concave 

 calyces whose boundaries are poorly defined and only slightly elevated. 

 Calyces with a well marked, rather deep and comparatively broad central 

 pit, averaging nearly 1 cent, in width, having steep, at times almost 

 vertical sides and a flat bottom. Tabulae, forming a well defined axial 

 area, flat or slightly convex, turned down at their edges, as broad as the 

 pit is wide, about sixteen in a space of 5 mm. Septa numbering from 

 forty to about fifty-two, lamellar and uninterrupted in a narrow area 

 surrounding the tabulae, of two orders, the primaries reaching the centre 



