1849.] EGERTON ON THE GANOIDEI HETEROCERCI. 9 



mountable obstacle not only to a definition of its generic characters, 

 but to a determination of the family in which it ought to be placed. 

 It is not even known whether the tail was homocerque or heterocerque, 

 a point of some importance as bearing upon the value of this character 

 as a criterion of the age of strata, since some of the species are con- 

 fined to the Triassic period. Agassiz has described three* species 

 from the Muschelkalk and Keuper of Germany, two of which occur 

 also in the bone-beds of Old Passage and Axmouth, and at Newtown 

 Limavady in Irelandf . He mentions another species as having been 

 found in the coal shale near Leeds. Count Miinster has described 

 a fifth species from the Trias at St. Cassian which he names G. bipli- 

 catus. 



Genus Coccolepts, Ag. 



This genus is liable to be overlooked by those having occasion to 

 consult the work of Agassiz, as it is described in a supplemental 

 chapter at the end of the Observations on the Heterocerque Lepidoids; 

 it is however worthy of especial notice as being the only one of this 

 family hitherto found in any stratum more recent than the Trias. C. 

 BucMandi is an unique specimen in the collection of Dr. Buckland 

 from the Oohte of Solenhofen. 



Amblypterus, Ag. 

 Agassizi, Miinster 

 eupterygius, Ag. . . 



lateralis, Ag 



latus, Ag 



macropterus, Ag,. . 

 nemopterus, Ag. . . 

 Portlocki, Egert. . . 



punctatus, Ag 



striatus, Ag 



Summary of Genera and Species. 



. . p. F. vol. ii. p. 105 Muschelkalk Esperstadt, Thuringia. 



. . P. F. vol. ii. p. 36 Coal formation Saarbrtick and Lebach. 



. . P. F. vol. ii. p. 39 Coal formation Saarbrtick and Lebach. 



. . P. F. vol. ii. p. 37 Coal formation Saarbrtick and Lebach. 



. . P. F. vol. ii. p. 31 Coal formation Lebach and Borschweiler. 



. . P. F. vol. ii. p. 107 Coal formation Nevvhaven. 



. . Geol. Journ.vol. vi. p. 2. . Coal formation Moyola, Moyheeland and 



Maghera. 



. . P. F. vol. ii. p. 109 Coal formation Newhaven. 



. . P. F. vol. ii. p. 1 1 1 . . . . . Coal foi-mation Newhaven. 



Eurynotus, Ag. 



crenatus, Ag P. F. vol. ii. p. 154 Coal limestone Burdie House. 



fimbriatus, Ag P. F. vol. ii. p. 1 57 Coal formation Newhaven. 



Pal^oniscus, Ag. 



angustus, Ag P. F. vol. ii. p. 57 Coal shale Autun. 



arcuatus, Egert Geol. Journ. vol. vi. p. 7. . Coal shale Goldlauter. 



Beaumonti, Jg- Geol. Journ. vol. vi. p. 6. . Coal shale Autun. 



Blainvillei, Ag P. F. vol. ii. p. 18 Coal shale Autun. 



carinatus, Ag P. F. vol. ii. p. 104 Coal-measures Newhaven. 



catopterus, Ag Geol. Journ. vol. vi. p. 4. . Permian Rhone Hill. 



comtus, Ag P. F. vol. ii. p. 97 • ■ • •• • Magnesian limestone. East Thickley, &c. 



decerns, Egert Geol. Journ. vol. vi. p. 7- • Coal shale Auvergne. 



Duvernoy, Ag P. F. vol. ii. p. 45 Coal shale Munster-Appel. 



Egertoni, Ag Geol. Journ. vol. vi. p. 5. . Coal shale North Stafford. 



clegans, Sedgw P. F. vol. ii. p. 95 Magnesian limestone. East Thickley, &c. 



Freieslebeni, Ag P. F. vol. ii. p. 66 Kupferschiefer Mansfeld, Richelsdorf. 



Gelberti, Goldf. Beitrage Coal formation Heimkirchen. 



glaphyrus, Ag P. F. vol. ii. p. 98 Magnesian limestone. East Thickley, &c. 



lepidurus, Ag P. F. vol. ii. p. 64 Permian Scharfeneck, Ottendorf. 



longissimus, Ag P. F, vol. ii. p. 100 Magnesian limestone. Ferry Hill, Whitley. 



macropomus, Ag P. F. vol. ii. p. 81 Zechstein Ilmenau. 



niacrophthalmus, Ag P. F. vol. ii. p. 99 Slagnesian limestone. East Thickley, &c. 



magnus, Ag P. F. vol. ii. p. 78 Kupferschiefer Mansfeld. 



niegacephalus, Germ Ktiize Kupferschiefer ftlansfeld. 



minutus, Ag P. F. vol. ii. p. 47 Coal shale Munster-Appel. 



Monensis, Egert Geol. Journ.vol. vi. p. 5. . Coal shale Anglesea. 



* Gyrolepis giganteus is an Holoptychius, Poiss. Foss. vol. ii. part 2. p. 285. 

 t Portlock, Geol. Mem. p. 469. 



