402 MEMOIRS OF THE CARNEGIE MUSEUM. 



Subclass TELEOSTOMI. 



Order I. CROSSOPTERYGII. 



Family CCELACANTHID^. 



This family is remarkable among fishes for its conservatism and great lon- 

 gevity. From their first appearance in the Upper Devonian, the Coelacanthidse 

 range practically unchanged through the intervening formations to the Upper 

 Cretaceous. The most satisfactorily preserved remains are those obtained from 

 the Lias and Upper Chalk of England, and from the Lithographic Stone of Bavaria. 

 Those from the latter horizon have been exhaustively treated in a memoir by 

 Dr. Otto M. Reis of Munich.^ 



Genus Undina Mlinster. 



10. Undina penicillata Miinster. 



(For references to the synonymy see A. S. Woodward, Cat. Foss. Fishes Brit. 

 Mus., Part 11, p. 410.) 

 Four well-preserved examples of this somewhat rare form are comprised in 

 the Bayet Collection of the Carnegie Museum, and are cataloged under the fol- 

 lowing numbers: 4055, 4703 (in counterpart), 4791, and 4792. One of them is 

 interesting because it shows the outlines of the ossified air-bladder, but none dis- 

 plays features not previously known. 



Order HOLOSTEI (LEPIDOSTEOIDEI). 



Family SEMIONOTIDiE. 



To this family belongs a series of deep-bodied forms represented by Dapedius, 

 Tetragonolepis, Homoeolepis, etc., which attain a notable development in the Lias, 

 but become extinct with the last-named genus in the Upper Jura. But a solitary 

 example of Homoeolepis is laiown from Upper Jurassic rocks, and this is clearly 

 indicative of a new species, the description of which follows : 



Genus Homceolepis Wagner. 



A form in general resembling Tetragonolepis, but distinguished from it by 

 the much less protuberant character of the ventral region, the relatively lower 



^ 0. M. Reis, " Die Coelacanthiuen, mit besonderer Beriicksichtigung der im Weissen Jura Bayerns 

 vorkommenden Gattungen," Paleoutographica, Vol. XXXV, 188S. 



