358 



SYNOPSIS OF TUB CYPPINIDyTC OF PENNSYLVANIA. 



arctic are, firstly, the existence of the three tribes Cochlobori, Ccclophori, and Mcsocysti ; 

 as far as known the genera of the latter region, as well as those of the Palyeotropical, are 

 all referable to the tribe Epicysti. 



As regards the Epicysti we observe, first, the absence of types related to the true Cypri- 

 nus, or to Barbus, the most bulky species of the family, as well as the smaller size in gen- 

 eral of the American species, whether representative or peculiar ; third, the abundant 

 representation of the few species of Gobio and Bungia ; fourth, the abundance of forms 

 closely resembling the genera Squalius and Idus ; fifth, abundance of forms intermediate 

 between Cyprinidse with soft lips, and those with cartilaginous labial sheaths ; sixth, the 

 paucity of representatives of Abramis, and over the Eastern part of the area, of Alburnus. 



While, then, many of the genera of this district may be said to represent those of Eu- 

 rope, such appear to be separated by one prevalent ground of distinction, viz., the smaller 

 number of teeth than in the European types. The inner series is commonly 6-5 or 5-5, 

 sometimes 4-5 in the genera of the Old World ;* in our Eastern district two genera rise 

 to 5-5 and two to 4-5, while all the others possess 4-4, and many but a single row, which 

 is unusual among European genera. In the Pacific region, the genera of Cyprinida:, as of 

 many other animals, repeat the European structure and bulk more nearly. In the follow- 

 ing table the European genera are in italics ; the representatives are opposite : 



Inner series 5-5. 

 Gobin. 

 Buvr/ia. 

 Stilbe. 

 Abramis. 

 Blicca. 

 BUccoptis. 

 Pelectn. 

 Alburnus. 



Aspius. 

 Leuraspins. 



/(//IS. 



Scan/ in ins. 



Le.neiscMS. 



Squalius. 



5-4. 



Semotilus. 



4-4. 



Oeratichthys. 



Argyreus. 



Platygobio. 



Alb i, 



Clinostomus. 



Tehstes. 



Alburncllus. 

 Photogenis. 



Cyprinella. 



Hypsilepis. 



Ilybopsis. 



Codoina. 



Cochlognathus. 



Mcda. 



Phoxinus. 

 rhoxinus is rarely abnormally 4-4. Qirard gives 5-5 in Semotilus, but I have not yet observed it. 



