56 Prof. H, A. Nicholson — New Devonian Fossils. 



dichotomously for the most part at angles of about 40°, and anasto- 

 mose to form an open network, the meshes of which are oval or dia- 

 mond-shaped, and vary in length from three lines to three-quarters 

 of an inch. As in the preceding species, the network is not always 

 in a single plane, and the branches often coalesce at the nodes of the 

 network to form flattened sub-palmate expansions. Corallites small, 

 crowded, with thin walls, the calices sub-triangular, or, when worn, 

 markedly triangular, with the apex of the triangle directed towards 

 the base of the frond. About three calices in the space of one line, 

 measured either diagonally or vertically. The long diameter of the 

 calices is about one-fourth of a line or rather more, and the inter- 

 spaces between them, measured diagonally, are about half as much. 

 Alveolites Billingsi (See Fig. 6, c, which represents a fragment of the 

 natural size, in which the surface is somewhat worn) is allied to 

 A. ramulosa, but is distinguished by the larger size of the stems, the 

 dichotomous mode of division, the more open network, and the larger 

 size and closer arrangement of the corallites. From A. lahiosa, 

 Billings, it is distinguished by its reticulated form and more closely- 

 set calices. 



Locality and Formation. — Corniferous Limestone of Port Colborne 

 and Lot 6, Con. 1, Wainfleet. 



Genus Chaetetes, Fischer. 



Gen. cJiar. — Corallum ramose, massive, or incrusting, composed of 

 elongated basaltiform corallites, which are in close contact and are 

 not united by any ccBnenchyma. Tabulae well developed ; septa 

 absent ; no mural pores. 



The genus Chaetetes is nearly allied to Favosites, but is separated 

 by the absence of mural pores. Very similar in all essential respects 

 to Chaetetes is the genus Stenopora of Lonsdale, the differential cha- 

 racter of which is stated to be the presence of minute styliform pro- 

 cesses at the angles of the calices, whilst the corallites are contracted 

 at intervals in planes parallel with the surface, and the ridges bound- 

 ing the calices are granulated or tuberculated. Good authorities, 

 however, reject the genus Stenopora altogether, and refer the forms 

 placed here partly to Favosites and partly to Chaetetes. Lastly, the 

 genus Monticulipora has been founded by D'Orbigny, to include 

 species of Chaetetes which increase by gemmation, instead of fissi- 

 parously, as is ordinarily the case in the genus. 



In the present state of our knowledge it seems almost impossible 

 to separate these three genera ; or, at any rate, it is certainly often 

 impossible to decide positively, after the most careful examination 

 and comparison, to which of them a given specimen may actually 

 belong. In the Hamilton formation of Western Canada occur three 

 small corals, which are certainly referable to one or other of these 

 three genera, and which I shall provisionally consider as belonging to 

 the genus Chaetetes. 1 have been unable to identify any of the three 

 with previously described forms ; and I have, therefore, been com- 

 pelled, though with great reluctance, to consider them as new, though 

 from the insufficiency of many existing descriptions it may subse- 

 . quently be proved that they are some of them identical with forms 

 already known. 



