LOPHIID.E. XCVI. 173 



Next come the BatracJiians, animals bearing close relations to 

 the " central stem " of the fishes, now represented by the Dipnoi. 

 They are decidedly fish-like in their early conditions, but this stage 

 is ultimately outgrown. " The undivided cartilaginous coracoid of 

 Polyterus (a Dipnoan) has a tubercle articulating with diverging 

 rods; in the one we have the rudiment of the humerus, in the 

 other the representatives of the ulna and radius, while the undif- 

 ferentiated cartilage between the diverging rods is material for the 

 carpal bones, and in bones radiating from that cartilage are the 

 homologues of the metacarpals. The attempts of a primitive ani- 

 mal of such a type to travel on land might develop the fore-limb, 

 and a hind one would follow in sympathy with the other. Then we 

 would have the first of the quadruped vertebrates," the Batrachians. 

 (GUI.) 



NOTE. Page 47. The RED-HORSE or WHITE SUCKER of the Chesa- 

 peake region has the anterior rays of the dorsal elevated, the outline of 

 the fin decidedly concave. It is perhaps a distinct species from the 

 common Eed-Horse of the West and South desciibed in the text. It 

 may stand as 81. Moxostoma macrolepidotum (Le Sueur), and the Western 

 form, N. Y. to Dak. and Ga., as 81 (b). M. duqiwmei (Le Sueur). 



