Gaspare! on Helix Pomatia. 175 



but the former is not fecundated by this second copulation. In 

 short, in all my observations, both individuals do not produce at 

 the same period, but one of them at least tnenty or twenty-four 

 days after the other. I have been careful thoroughly to establish 

 this fact, which has escaped former observers, and which in some 

 toieasure diminishes the mifacle of the generation of Snails. It 

 proves them in fact to be hermaphrodite, but not simultaneously 

 fecundated. They are anatomically, however, strictly androgy- 

 nous. 



It is usually about the middle or latter end of May that they 

 unite, to produce their eggs in June. I believe they generally 

 lay but once in the year ; though I have known one produce a con- 

 siderable, and almost equal number on the 20th of June, and again 

 on the 4th of August. I have also found two united in Septem- 

 ber, doubtless after a previous generation : and those which laid 

 their eggs in the winter over my fire-place, had probably pro- 

 duced during the previous summer. 



The number of eggs at each laying varies, as far as I have 

 observed from 25 to 80. They are found in the nest, agglo- 

 merated, and slightly stuck together with mucus ; they are spheri- 

 cal, hard, opake and white; about the size of small peas, and 

 considerably resembling the berries of the misseltoe. They sxe 

 composed entirely of limpid albumen contained in a membrane 

 which is somewhat solid, and fibrous. Each es,g weighs about 

 three grains and a half. They sink in water, become wrinkled 

 in a dry atmosphere, and are preserved only in a moist situation. 

 Placed on burning coals, they swell, crackle, and become charred 

 without much smell ; they freeze at a similar degree of cold as 

 the white of birds' eggs ; though the mucus which envelopes them 

 freezes at a higher temperature. Boiling water coagulates the 

 albumen, and gives it a bluish tinge. Nitric acid turns the mucus 

 of a yellow colour, instantly dissolves the opaque envelope with a 

 brisk effervescence, and coagulates the albumen without the dis- 

 engagement of gas. 



The eggs deposited in the earth and exposed to damp, develop© 

 themselves without incubation like those of all the cold blooded 

 animals, but more or less quickly, according to the temperaturel 



