PAL.EONISCTTS, GYROLEPIS, A.ND PYGOPTERUS. 569 



since some of the species are confined to the Triassic period " *. 

 Subsequently, however, Sir Philip expressed an opinion that in 

 Gyrolepis " we have probably a heterocerque fish " f . 



More recently Dr. Karl Martin has advocated the view that the 

 Triassic scales known as Gyrolepis belong to SaurichtJiys, " because 

 the strongly marked sculpture of their surface (like the condition of 

 the teeth of SaurichtJiys) reminds us of that of the scales of 

 Acrolepis, and because hitherto neither teeth have been found 

 which could correspond to these scales of Gyrolepis, nor other scales 

 which could be ascribed to the teeth of SaurichtJiys." SauricJithys 

 itself is referred by Martin to the family Palseoniscidae on account of 

 the resemblance which the teeth and a fragment of a maxilla 

 figured by him bear to those of Acrolepis asper +. 



Finally, as I have already mentioned (p. 550), Prof. Victor Carus 

 has not only reunited Rhabdolepis, Troschel, to Amblypterus, Ag., 

 but has added, as synonyms of the latter, Gyrolepis, Colobodus, and 

 TJiolodus. I need not again point out how inconsistent it is 

 with the prevailing ideas of the limits of a genus to reckon as 

 congeneric with such a fish as Amblypterus latus scales like those 

 known as Gyrolepis, or teeth like those of Colobodus or Tholodus. 



From the preceding sketch of its history it is abundautly clear 

 that at present all definition of Gyrolepis as a genus is impossible ; 

 and under the circumstances it does seem to me better to follow the 

 example of Giebel in cancelling the term altogether. As regards 

 the Triassic species which have been so named, I must necessarily 

 leave the final determination of their position to continental palaeon- 

 tologists. But, as to the use of the name Gyrolepis in catalogues 

 of British Carboniferous fossils, there can, I think, be no doubt as to 

 the propriety of its entire abolition ; for, unless the Triassic scales 

 to which the name was originally given are really referable to 

 Acrolepis, there is no Carboniferous fish of which we have the 

 smallest evidence that it belongs to the same genus with them. 

 What, then, is the real nature of the one Carboniferous species 

 which has been definitely named Gyrolepis, but which has hitherto 

 remained undescribed ? 



The name Gyrolepis Rankinei occurs in Agassiz's general list of 

 fossil Ganoids, the formation and locality quoted being the Coal- 

 measures of Leeds. Neither description nor figure is given ; and the 

 original specimen seems now, unfortunately, to be lost or unknown. 

 But in Morris's ' Catalogue of British Fossils ' (p. 273) Lanark- 

 shire is given as an additional locality for this species ; and on 

 inquiring of Dr. Rankin, of Carluke, and Mr. Grossart, of Sals- 

 burgh, in that county, I learn that Agassiz, when in Scotland, also 

 designated as G. Rankinei a specimen in Dr. Eankin's collection. 

 To these gentlemen I am indebted for the opportunity of examining 

 portions of the original Lanarkshire specimen, along with others 



* Quart. Journ. Geol. Soc. vol. vi. 1850, pp. 8, 9. 



t Pec. Greol. Survey, viii. 1855, text accompanying pi. ix. p. 3. 



1 Zeitschrift der deutschen geol. G-csellscli. xxy. (1873). 



2v2 



