DEVONIAN EOCKS OP WESTERN CANADA. 47 



the base of the mass are large and -unequal in size, whilst those at the 

 summit are on the average smaller, and are nearly equal in size. 

 The same distinguished palaeontologist has also pointed out that the 

 younger pyriform colonies also pass, by an equally perfect transition, 

 into elongated cylindrical forms, often of considerable length. Both 

 these statements I am enabled to confirm from my own observations. 



Besides the typical examples of F. Forhesi which I have just 

 described, there occur not uncommonly others Avhich I cannot at 

 present separate from this species, though they present several more 

 or less well-marked peculiarities. The corallum in the examples in 

 question resembles in shape the more ordinary individuals of F. Goth- 

 landica, being circular and flattened above, and springing fi-om a 

 pointed and attenuated base, which was doubtless enclosed in an 

 epitheca. The coi'allites are not distinctly circular, but are cylindroi- 

 dal or sub-prismatic, and they are nearly eqvial in size, having an 

 average width of one line. Interspersed, however, with the ordinary 

 corallites are some smaller ones having a diameter of half a line or a 

 little less. The mural pores appear to form a double series. The 

 radiating septa are well marked, and form a series of about twelve 

 strong ridges which run longitudinally in the interior of the corallites. 

 These septal ridges are crossed by rudimentary tabulae in the form of 

 short spine-like lamellae, about three or four in the space of a line 

 and not placed on the same level in contigvious ridges. It is possible 

 that these forms are specifically distinct from those which I have here 

 referred to F. Forhesi : but I do not feel that it is safe to separate 

 them at present. 



Locality and Formation. — Corniferous Limestone, Port Colbornc, 

 and lot 6, con. 1, Wainfleet. 



TV. Faa'OSItes hemispherica (Yandell and Shumard). 

 In its essential characters, this species is very closely allied to 

 F. Gothlandica. Externally, however, it may in general be distin- 

 guished from the latter by the much smaller size of the corallites, 

 which are usually only from one twenty-fourth to one twentieth of 

 an inch in diameter, though they sometimes reach one liiae. Inter- 

 nally, the species is distinguished by the fact that the tabulae are 

 incomplete, very thin and closely set, usually extending only about 

 half way across the corallite, and often interlocked towards its centre. 

 Some of the tabulae, however, are usually complete. The mural pores 



