UMBE.] CANADIAN PALAEOZOIC CORALS. 21 



lateral angles ; tabulse complete, transverse or somewhat oblique ; septa 

 occurring as spines or longitudinal ridges, seldom in the form of squamulse ; 

 attached centrally below and with a basal epitheca. 



In the genus Alveolites there is no expansion of the corallites at the 

 calyces nor is there any thickening of the walls near the surface. The 

 calyces are typically subtriangular and oblique to the surface, although in 

 some species this obliquity is less apparent, as is also the compression of 

 the corallites. The pores and tabulse, septal spines or squamulse are as a 

 general rule not so numerous as in Favosites whilst the development of 

 longitudinal ridges forms one of the features which distinguish this genus 

 from Favosites and suggests its near relationship to Cladopora. 



Alveolites Labechei, Milne-Edwards and Haime. 



Alveolites Lahechci, Milne-Edwards and Haime. 1851. Polpy. Poss. des Terr. Palseoz. , 



p. 257. 

 M II Milne-Edwards and Haime. 1855. Brit. Foss. Corals, p. 262, pi. 



LXI., figs. 6, 6a, 66. 

 M M Billings. 1866. Cat. Sil. Foss. of Antioosti, p. 33. 



In division 3 of the Anticosti group at South Point, Anticosti, and in 

 division 4 at South-west Point and at the Jumpers, Anticosti, is found in 

 abundance an Alveolite which was identified by the late Mr. Billings with 

 this species. An Alveolite similar in structure to the Anticosti one is found 

 at Fossil Hill, Manitoulin Island, Lake Huron and at Skunk Island off 

 the south-western end of Manitoulin Island, also a little further west at 

 Point Detour and at Owen Sound, Ont. A small specimen which pro- 

 bably also belongs to this species was found at TAnse au Gascon, Bale des 

 Chaleurs, in rocks that have been assigned to the Lower Helderberg forma- 

 tion. The specimens from Skunk Island, Manitoulin Island, Point Detour 

 and Owen Sound are from the Niagara formation, and those from Anticosti 

 from the probable equivalent of that formation on the island. 



A specimen that is thought to belong to this species was collected on 

 the north-east side of Lake Winnipegosis (Station 227, No. 198) by J. B. 

 Tyrrell, in 1889 (Silurian). 



The corallum of the Canadian representatives of this species takes the 

 form of a low spreading mass, attached centrally at the base, with a some- 

 what convex upper surface, and a flat concentricallj' wrinkled lower sur- 

 face with a thin epithecal covering ; a specimen from South-west Point, 

 Anticosti, has a breadth of about 8 inches with a thickness of nearly 

 2 inches at the centre. Other specimens, some of them from Mani- 

 toulin Island and vicinity, depart from this form of growth and have a 

 less symmetrical shape ; they are frequently much thicker without a cor- 



