[MATTHEW] PALEOZOIC BATRACHIAN FOOTPRINTS 115 



retained for T. heterodadylis. As this request was made (1845-46) 

 before the present rules of nomenclature were established, it seems 

 to the author that this request should be respected; he has, therefore, 

 adopted this name for the group. The next name in point of 

 antiquity would be Sauropus used by Isaac Lea in 1855 for *S'. primœvus, 

 a species closely allied to King^s type, but having an interrupted "tail" 

 mark. 



Group 6 has many representatives: Thenaropus lieterodactylis, 

 King may be taken as the type of this group — PL I., figs. 1 and 3 — 

 which contains also Sauropus primœvus, King; Collettosaurus India- 

 nensis, Cox, and Notolacerta Jacksonensis, Butts. A new species from 

 the Joggins, Thenaropus (?) McNaugMoni, seems to fall here. In this 

 group the toe marks are heavier and shorter than in the preceding one. 



Group 7, also has five toes on the hind foot and four on the fore 

 but the impressions left are broader and more massive than those of 

 fhe preceding group. Limnopus vagans, Marsh, may be taken as the 

 type of this group. — PI. III., fig. 3. 



Group 8, includes forms which have four toes on both fore and 

 hind feet, and is well represented by Marsh's species Baropus lentus — 

 PL III, fig. 6. — B. unguifer, a new species from Joggins, N.S., placed 

 here provisionally, is perhaps the type of another genus.' 



Group 9, is typified by a curious little footprint described by 

 Marsh, Nanopus caudatus, from the coal measures of Kanz as PL III., 

 figs. 5 and 5a. — Sauropus Sydnensis, Dawson, from Gape Breton, N.S., 

 by the number of its toe prints would fall here, but it differs in impor- 

 tant respects. It may be compared with King's Spliœropezium thœro- 

 dactylum, which, however, has more numerous toes. 



Group 10 is instituted for a part of the tracks described by Sir Wm. 

 Dawson, under the name of Hylopus, doubtfully. They do not agree 

 with his diagnosis of that genus, and they differ from the common 

 omithoid reptilian tracks' of the Trias in the breadth of the palm, and 

 the obscurity of both it and the toes — PL II., fig. 3. They are tem- 

 porarily placed in a Triassic genus. 



As representative of Group 11, the two footmarks described by 

 King under the name of Ornithichnites, may be taken — PL II., fig. 1 — 

 with tracks resembling those of certain birds. Crucipes parva of E. 

 Butts, may be included here notwithstanding the supposed heavy tail 

 mark. 



^ This will be described as genus Barillopus. 



