ZOOLOGY. 233 



Free Martins. 



When a cow produces twins, their organs are fre- 

 quently imperfect, and they are incapable of procre- 

 ation, particularly when one happens to be a male, 

 and the other a female. Such examples are termed 

 Free Martins. 



Eggs. 



The manner- in which the eggs of birds are impreg- 

 nated has not been satisfactorily ascertained. With 

 the exception of the cicatricula, (the hollow at the 

 large end,) a bird, in the absence of the male, can 

 produce an egg, but it is unfertile. In birds, one 

 union suffices for the production of impregnated eggs 

 during the period of laying ; in the aphis, or plant- 

 louse, it suffices until the ninth generation. 



The Guimero Monster. 



The mules of Sicily are strong and excellent, and 

 in their attention to these, the Sicilians provide the 

 finest asses that can be procured ; but the guimero, 

 or monster between a horse and a cow, or bull and a 

 mare, though reared in Italy and Africa, is not es- 

 teemed in Sicily, it having proved more sluggish and 

 obstinate than the mule.* (Capt. Smyth's Sicily.) 



The Dugong. 



The habits of life of the manatee of the West In- 

 dies, place it between the dugong of the East Indian 

 seas and the hippopotamus. It has no tusks, and 

 feeds upon plants growing at the mouths of large 

 rivers. 



The dugong is the only animal yet known that 

 grazes at the bottom of the sea without legs. It is 



* Query : Is the existence of this animal satisfactorily esta- 

 blished ? Dr. Johnson says, " Jumart, the mixture of a bull and 

 a mare," and quotes Locke as his authority. 



