BIRTH, GROWTH AND REPRODUCTION OF OYSTERS. IOI 



upon this state depends whether the animal is viviparous, 

 ovoviviparous, or oviparous. The first of these terms refers 

 to animals which bring forth their young alive, derived 

 from two Latin words, vivus, alive, and pario, to bring forth. 

 The second has the addition of ovo to it, from ovum, an 

 egg, and applies to animals in which the young are hatched 

 from eggs in the interior of the parent, without having any 

 connexion with a uterus (or a womb.) The third, oviparous, 

 to animals which bring forth eggs which are afterwards 

 hatched. 



Of the first mode of reproduction we have examples 

 in man and other mammalia ; of the second, among infu- 

 soria and some other animalcule, numbers of which may be 

 observed in any puddle ; and of the third, birds form a 

 good example. 



* 



All animals are either monoecious or dioecious : these 

 terms were originally applied by Linnaeus to two Classes of 

 plants, the former having the male and female organs in 

 different flowers on the same plant ; the latter having the 

 sexual organs distinct on separate plants : these terms are 

 now applied also to animals, (d} 



The first point to be considered is, to which of the 

 first-named divisions the oyster belongs, viz. : viviparous, 

 ovoviviparous, or oviparous. My own observations tend to 

 establish the fact that they are ovoviviparous, in support of 

 which view I shall now give a few extracts from the note- 

 book of Professor Eyton, referring to numerous examina- 

 tions of the ovaries previous to the expulsion of the young. 



" May 19. Dissected and examined a large number of 



(d) It may not be out of place here to remind the reader that, in 

 Nature, no two animals, however like each other in figure or confor- 

 mation, are of manner entirely the same. 



