44 Isospondyli 



ceous of Mount Lebanon. Many other species are found in the 

 European and American Cretaceous rocks, but are known from 

 imperfect specimens only. 



Sardinius, an American Cretaceous fossil herring, may stand 

 near Spaniodon. Rhacolepis buccalis and Notelops brama are 

 found in Brazil, beautifully preserved in concretions of cal- 

 careous mud supposed to be of Cretaceous age. 



The extinct family of Pachyrhizodontidce is perhaps allied 

 to the Elopida. Numerous species of Pachyrhizodus are found 

 in the Cretaceous of southern England and of Kansas. 



The Albulidae. The Albulida, or lady-fishes, characterized by 

 the blunt and rounded teeth, are found in most warm seas. 



FIG. 31. The Lady-fish, Albula vulpes (Linnseus). Florida. 



Albula vulpes is a brilliantly silvery fish, little valued as food. 

 The metamorphosis (see Fig. 112, Vol. I) which the larva under- 

 goes is very remarkable. It is probably, however, more or less 

 typical of the changes which take place with soft-rayed fishes 

 generally, though more strongly marked in Albula and in certain 

 eels than in most related forms. Fossils allied to Albula, Albula 

 oweni, Chanoides macropomus, are found in the Eocene of Europe ; 

 Syntegmodus altus in the Cretaceous of Kansas. In Chanoides, 

 the most primitive genus, the teeth are much fewer than in 

 Albula. Plethodus and Thryptodus, with peculiar dental plates 

 on the roof and floor of the mouth, probably constitute a dis- 

 tinct family, Thryptodontidcc. The species are found in Euro- 

 pean and American rocks, but are known from imperfect speci- 

 mens only. 



The Chanidae. The Chanida, or milkfishes, constitute another 

 small archaic type, found in the tropical Pacific. They are 



