502 
ACTIXOPIERYGII. 
1833. Acrolepis sedgwicki , L. Agassiz, Neues Jalirb. p. 476, and Poiss. 
Foss. vol. ii. pt. i. p. 11. 
1833. Gyrolepis asper, L. Agassiz, ibid. p. 473, and ibid. p. 6. 
1835. Acrolepis sedgwickii, F. A. Qnenstedt, Wiegaiann’s Archiv. 
Naturg. vol. ii. p. 92. 
1839. Palceoniscus dunkeri, G. A. Kurtze, Comment. Petrefact. Mans- 
feld. pp. 16,37, pi. i. 
1840. Palceoniscus dunkeri , E. F. Germar, Verstein. Mansfeld. Kupfer- 
scliief. p. 19, figs. 1-5. 
1841. Acrolepis asper , L. Agassiz, Neues Jalirb. p. 614. [Britisli 
Museum.] 
1842. Acrolepis dunkeri, G. von Munster, Beitr. Petrefakt. pt. v. p. 40. 
(P) 1842. Acrolepis angustus, G. von Mimster, ibid. p. 40. [Palaeonto¬ 
logical Museum, Munich.] 
(?) 1842. Acrolepis giganteus, G. von Munster, ibid. p. 41. [Ditto.] 
1844. Acrolepis sedgwickii, L. Agassiz, Poiss. Foss. vol. ii. pt. ii. p. 80, 
pi. lii. (plate published 1839). 
1844. Acrolepis asper, L. Agassiz, ibid. p. 81. 
1848. Acrolepis sedgwickii, C. G. Giebel, Fauna der Vorwelt, Fische, 
p. 241. 
1848. Acrolepis asper, 0. G. Giebel, ibid. p. 241. 
1850. Acrolepis sedgwickii, Sir P. Egerton, in King’s Permian Foss. 
(Pal. Soc.), p. 234, pi. xxv. 
1861. Acrolepis sedgwicki, H. B. Geinitz, Dyas, p. 13. 
1861. Acrolepis asper, angustus, and giganteus, II. B. Geinitz, ibid. 
pp. 13, 14. 
Type. Caudal portion of fish; olim Witham Collection. 
The type species, attaining a length of about 0'7. Maximum 
depth of trunk contained about six times in the total length. Head 
and opercular apparatus occupying one-fifth of the total length; 
snout obtusely pointed; hinder expansion of maxilla three quarters 
as high as broad, truncated above, its postero-inferior portion pro¬ 
duced downwards in a small rounded expansion, bearing smaller 
teeth than the other part of the dentigerous border; large teeth 
short and stout, but acutely pointed: ornamentation of cranial, 
facial, and opercular bones almost uniform, consisting of coarse 
tuberculations, with a tendency towards elongation and partial 
fusion into parallel rugas; tubercles of rostral region mostly rounded, 
those bordering the jaws the smallest. Pelvic fins about half as 
large as the pectorals, situated much nearer to the anal than to the 
latter; dorsal and anal fins deeper than long, of nearly equal size, 
the dorsal precisely opposed to the space between the pelvic fins 
and the anal, to which its base-line is almost equal in extent. 
Scale-ornament very coarse, the flank-scales each marked by about 
six broad, rounded, antero-posterior ridges, of which those on the 
