1909-] THE CAYUGA LAKE BASIN, N. Y. 383 



northwest in the early morning, the wind continues from the southeast and 

 begins to increase in force, the approach of a storm is indicated. While rain 

 begins most frequently with falling barometer, the heaviest rainfall often 

 comes, especially in the warmer months, after the turn of the barometer from 

 falling to rising. 



Richard's registering hygrometer shows that in spring and summer the 

 humidity sometimes decreases before rain, but rapidly increases after rain 

 begins ; in spring rain begins with relative humidity from 50 to 98 per cent., 

 and in summer it may be as low as 50 per cent, one hour before rain begins. 

 In autumn the effect of day and night seems greater than the influence of 

 passing storms, and rain will begin with relative humidity as low as 50 per 

 cent, one hour before rain. In winter there is usually an increase in humidity 

 from one half to four hours before rain, and dry snow will begin with relative 

 humidity as low as 40 per cent. 



Cirrus clouds are reliable indications of precipitation in all seasons, but 

 are liable to be obscured by lower clouds of local formation in the colder 

 portion of the year. These clouds appear moving from the west in the 

 spring and winter, from the northwest in summer, and from the southwest 

 in autumn, twenty-four to thirty-six hours before precipitation begins. Special 

 characteristics of clouds have not been noted except in connection with 

 cirrus clouds. 



Frost is likely to damage fruit or other crops in May and September. 

 Heavy frost is generally preceded by high barometer, low temperature and 

 humidity, very high wind and clear weather. 



The Fishes of the Basin. — The fish fauna of the basin comprises 

 65 species distributed among 21 families, as follows: 



Petromyzonidse 2 species. Umbridae i species. 



Acipenseridae i " Esocidse 2 



Lepisosteidae i " Poeciliidae 



Amiidas i " Gasterosteidae 



Siluridse 5 " Percopsidae 



Catostomidae 4 " Atherinidas 



Cyprinidae 19 " Centrarchidae 



Anguillidae i " Percidje 



Clupeidae I " Serranidae 



Salmonidae 5 " Cottidae 2 



Gadidas i species. 



As yet too little is known of the fish fauna of the finger lakes to 

 draw any definite conclusions concerning the general distribution of 

 species or the relation of these faunas to others. Lake Cayuga and 

 Seneca River have water connection with Lake Erie and the Hudson 

 River through the Erie Canal ; with Lake Ontario both through river 

 and canal (Oswego) ; with the Susquehanna system through several 



