690 THE AMERICAN NATURALIST. [Vol. XXXVII. 



barb, like that of a fishhook. There seem to have been no 

 vertebrae, and the body has been covered with bony plates. 



The Macrosemiida: and Oligopleurida'. scantily represented at 

 Hakel, have not yet been found at either Sahel Alma or Hajula. 

 Some of the fishes of the Upper Cretaceous had already acquired 

 many of the characters which are found in our modern forms. 



fulcra, and in many cases the rays had become spinous. A 

 number of the families that still persist hail already come into 



known by the tarpon of our southern waters, are recognized in 

 eight species at Sahel Alma, three at Hakel, and one at Hajula. 



None of the species begins to attain the size of the tarpon. 

 The Ichthyodectidae, a family close to the Chirocentridae, is 

 thought to be represented at Hakel and Hajula by a species 

 which Woodward calls Ichthyodcctcs libnmcus, but which the 



a biter that gets a good living. It grew to a size somewhat 

 greater than that of the shad. 



Ctenothrissa is a genus which stands as the type of the 

 Ctenothrissidae. It possessed many of the structures that are 



It ha/serrated scales, and the ventral fins had been moved for- 

 ward to a position just below the pectorals. The writer has 



from Hajula. It is characterized by the possession of very high 

 dorsal and anal fins ; and the ventral rays likewise were greatly 

 elongated. 



The Clupeida:, so abounding in genera and species in the salt 

 and fresh waters of our time, were present in force during the 



