﻿DlPLACANTHlD-«. 



33 



Type. Fragment of spine. 



An undefined species known only by fragments of fin-spines 

 more closely resembling those of CUmatius than of any other genus. 

 The longitudinal ridges upon the spine are notched, the intervals 

 being very short immediately above the base, and at least twice as 

 long as these throughout the more distal portion. 



Form. <$f Loc. Lower Old Red Sandstone (Passage Beds) : Here- 

 fordshire and Worcestershire. 



P. 5092. Two imperfect spines ; Tin Mill, Downton, near Ludlow. 



Presented by J. E. Lee, Esq., 1885. 



Climatius (?) latispinosus (Whiteaves). 



1881. Ctenacanthus latispinosus, J. F. Whiteaves, Canadian Naturalist, 



n. s. vol. x. p. 99. 

 1889. Ctenacanthus latispinosus, J. F. Whiteaves, Trans. Roy. Soc. 



Canada, vol. vi. sect. iv. p. 95, pi. x. fig. 3. 

 1889. Climatius latispinosus, A. S. Woodward, Ann. Mag. Nat. Hist. 



[6] vol. iv. p. 183. 



Type. Detached fin-spines ; Geological Survey of Canada, Ottawa. 



An undefined species known only by detached fin-spines, which 

 attain a relatively large size. The spines are broad, nearly 

 straight, with finely tuberculated ridges and prominent posterior 

 denticles. 



Form. Sf Loc. Lower Devonian : Campbellton, New Brunswick. 



P. 6223. Imperfect spine. Presented by the Director of the Geological 



Survey of Canada, 1890. 



A doubtful spine is also described as follows : — 



Climatius aculeatus, E. von Eichwald, Leth. Rossica, vol. i. (1860), 

 p. 1602, pi. lvii. fig. 20. — Old Red Sandstone ; Slawjanka, 

 near Pawlowsk, St. Petersburg. [University of St. Peters- 

 burg.] 



Genus PAREXUS, Agassiz. 

 [Poiss. Foss. Y. G. R. 1845, p. 120.] 



Body deeply fusiform, laterally compressed ; caudal fin large and 

 powerful. Teeth minute or absent. Fin-spines robust, marked with 

 coarse longitudinal ridges ; first dorsal spine enormously developed, 

 with large posterior denticles ; several pairs of free spines on the 

 ventral aspect between the paired fins. 



The first dorsal fin-spine only was known to Agassiz, and the 

 genus thus remained imperfectly defined until 1864, when Powrie 

 discovered a complete example of the type species. 



PART II. d 



