CONCLUSIOAS. 91 



CONCLUSIONS.* 



lu the coarse of the itivestigatioiis detailed in this paper, some light 

 has been tlnowu on the laws wljich goveru the distribution of fresh- 

 water fishes in general. The writer has collated the known facts into a 

 series of general propositions, which, without any pretense to exhaust- 

 ivenoss or to originality, are here briefly stated. It may be premised 

 that some of these propositions are only half truths, to be more com- 

 pletely stated when our knowledge of the subject shall be increased. 

 Most of the statements also refer chiefly to the smaller and non-migratory 

 ashes, espQd'niUy the UtheostoniatidcB, Gcntrarchiclce, and Cijpriiiida}. Our 

 knowledge of the range of the larger Catostomidw and Siluridce is still 

 very meagre. 



For the first statement of several of the following propositions, we ai^e 

 indebted to Professor Cope, who has ably discussed the subject of the 

 distribution of fishes in his*paper on the Fishes of the Alleghany Region 

 of Southwest Virginia, Journ. Acad. :N^at. Sc. Phila. LSG8, i)p. 239-247. 



I. In the case of rivers flowing into the ocean, the character of the 

 faunse of the upper waters, compared one with another, bears uo, or 

 very little, relation with the places of discharge. In illustration of this 

 we may note («) the similarity of the faunsB of the Chattahoochee and 

 Altamaha, as compared with the Chattahoochee and Alabama. The 

 fauna) of Wisconsin Eiver and of Ived liiver of the North are ver^' similar. 



II. Eiver-biisius having a similar discharge into some larger river or 

 lake h.ive a similarity of fauna, due to this fact, and, in general, other 

 things being equal, the nearer togt^her the places of discharge, if in 

 fresh water, the greater the similarity. The almost identical faunas of 

 the Catawba and the Saluda will illustrate this. 



III. Piirallel rivers tributary to the same stream have, other things 

 being equal, more in common than streams coming from opposite dii^ec- 

 tions. The Wabash and Miami have more in common than either has 

 with the Kentucky. 



IV. The higher or the older the water-shed between two streams, the 

 fewer species are common to both. (This matter needs lurther investi- 

 gation.) 



V. Certain species, not inclu<ling "species of general distribution", 

 occur on opposite sides of eveu the highest watersheds. This fact was 

 first noticed by Professor Cope. The occurrence of Luxilns coccogenis, 



* Au abstract of I he reraaitiiGg part of this paper appeared ia the American Naturalist 

 for October, 1877 (pp. (307-613). For this pait, Professor Jordau is uloue responsible. 



