Trof. H. A. Nicholson — On the Genus Fawsites. 569 



times (not alwajj-s) a single row of mural pores, but whicli differ 

 in having nearly rounded or cylindrical corallites of very unequal 

 size, whilst the tabulae are only represented by short projecting 

 lamellae, imparting a peculiar and characteristic appearance to the 

 inner surface of the corallites. 



It is the first of these groups which is usually regarded as the 

 type-form of jF'. basaltica, Goldf. ; and the only question is whether 

 these are separable from F. OotJilandica, Lam., or not. The author 

 next discusses the opinions of various writers on this point. 



The second group was separated by MM. Milne-Edwards and 

 Haime from the first under the head of F. Forhesi; but Mr. Billings 

 re-united them under the former name of F. basaltica, Goldf. 



Prof. Nicholson considers that F. Forhesi, M.-Ed. and H., is a good 

 species, and proceeds to describe it. 



III. Favosites Forhesi, Edw. and H. — Coral! um forming sphe- 

 roidal, pyriforra, cylindroidal, or depressed hemispheric masses, 

 composed of corallites, generally circular or cylindrical in shape, 

 and usually very unequal in size ; mural pores in two alternating 

 rows, rarely in a single row ; tabulae mostly rudimentary and re- 

 presented by very close-set projecting lamellae, which roughen the in- 

 terior of the corallites ; radiating septa represented, sometimes clearly, 

 sometimes indistinctly, by a number of longitudinal ridges or striae. 



The corallites are large and small, each larger one being surrounded 

 by an incomplete ring of smaller, which vary considerably in size, 

 whilst the larger are pretty constant ; the mural pores often cannot 

 be made out. The tabulae are present in an incomplete and rudi- 

 mentary form, projecting a short way into the coral lite, giving it a 

 peculiar and easily-recognized appearance, and in one specimen in 

 Prof. Nicholson's possession extend half across the corallite, often 

 bifurcating or interlocking at their free ends, and sometimes extend- 

 ing right across. The radiating septa are quite rudimentary, and 

 when discernible have the form of obscurely marked longitudinal 

 striae. Lastly, the author has observed in some sjoecimens, espe- 

 cially those of a cylindroidal or clavate form, the peculiar feature 

 that the calices of a greater or less moiety of the colony are closed 

 by an epitheca, closely resembling what is observed in F. turhinata, 

 Billings. 



Prof Nicholson next mentions some other specimens which present 

 several peculiar features, but which he cannot at present separate 

 from this species. 



Locality and Formation — Corniferous Limestone, Port Colborne, 

 and lot 6, con. 1, Wainfleet. 



IV. Favosites hemispherica, Yandell and Shumard. — In its essen- 

 tial characters this species is closely allied to F. GotJilandica ; but 

 the corallites are much smaller in size and the tabulae incomplete, 

 very thin, and closely set, usually extending only half-way across the 

 corallite, and often interlocked towards its centre. Usually, how- 

 ever, some of the tabulae ai-e complete. The mural pores are stated 

 to be in one, two, or three rows (M.-Edw. and H. and Billings), but 

 the author has not detected any in the Canadian specimens which 

 he has seen. According to Milne-Edwards and Haime, also, there 



