[lambk] PROGEESS of VERTEBRATE PALAEONTOLOGY 17 



described in 1844 from Scotland. The Canadian species is interesting 

 on account of its having clearly indicated oral appendages, described 

 by Whiteaves and also by A. S. Woodward. This genus differs from 

 Pteriehthys principally in the proportions of the plates, the direction 

 of the sensory canals and the relatively longer lateral appendages which 

 are supposed to be modified and highly specialized head spines. 



As in the Lower Devonian, the Diplacanthidœ and Acanthodidse 

 are present, the former represented by the typical genus; the species are 

 DiplacantMis striatus, D. horridus, Acaniliodes afjinis and A. concin- 

 nus, all four from Scaumenac bay. The Chimseroid genera Ptyctodus 

 and Bliyncliodus are from the Upper Devonian of Manitoba, the former 

 also occurring in rocks of the same age in Ontario. The Dipnoans are 

 made conspicuous in this fauna by the presence of four species belonging 

 to the four genera, Scaumenacia, Coccosteus, Aspidictliys and Dinich- 

 tJiys. Scaumenacia curta from Scaumenac bay is a Sirenoid of the 

 family of Phaneropleuridse. The Arthrodiran lung-fishes Coccosteus 

 canadensis from Scaumenac bay, Aspidictliys notabilis from Ontario 

 and Manitoba, and Dinichihys canadensis from the same provinces, 

 were probably worthy representatives of this extinct and highly spe- 

 cialized order. Holoptychius, Eusthenopteron, Onychodus and Cheiro- 

 Icpis, Teleostomatous fishes, complete the list of the known Devonian 

 genera of this country. Of the Crossopterygians Holoptychius quehec- 

 ensis and Eusthenopteron foordi are from Scaumenac bay, and an 

 undetermined species of Onychodus is from the Cuboides zone of thû 

 Devonian of ^Manitoba. The Actinopterygian, Cheirolepis canadensis 

 of the suborder Chondrostei still further accentuates the richness of 

 the fish-fauna of Scaumenac bay. 



The well-known Eusthenopteron foordi exemplifies in an admirable 

 manner a modified " archipterygial " type of fin structure in the pec- 

 torals. In the type specimen in the museum of the Geological Survey, 

 the relation of the unfused radial supports, in the unpaired fins, to 

 the basais which connect directly with the axial skeleton, is particu- 

 larly well shown. Dr. Whiteaves's descriptions supplemented by the 

 results of Dr. A. S. Woodward's study of additional material from the 

 type locality, and critical observations on the fin structure generally, 

 by Professor Bashford Dean,^ have made this species one of the best 

 known of the Devonian Crossopterygians. 



The Carboniferous rocks of eastern Canada have yielded a highly 

 important vertebrate fauna comprising a variety of fishes and a wealth 



* Fishes, living and fossil. An outline of their forms and probable re- 

 lationships, by Bashford Dean, New York, 1895. 



Sec. IV., 1904. 2. 



