61 



PROCESS OF DEVELOPMENT IN FISHES. 



In leaving these slight anatomical sketches, and 

 turning to the more interesting field of Physio- 

 logy, we shall first direct attention to the different 

 methods by which the grand process of reproduc- 

 tion is regulated in fishes. In the last part of Pro- 

 fessor Miiller's admirable treatise on Physiology, 

 such a flood of light is thrown upon the subject 

 of development, that we cannot lose the opportu- 

 nity of recommending it to the attention of all 

 who are curious in the astonishing secrets of Na- 

 ture's work ; and, still more to enhance this re- 

 commendation, we shall endeavour to supply a 

 specimen of the information which may be gleaned 

 from his original and philosophical pages. 



The process of the development of the ova of dif- 

 ferent animals appears to be exhibited under three 

 distinct forms. First, in Oviparoits animals, the 

 ova are expelled from the system of the mother, and 

 undergo development independent of it, the requi- 

 site nourishment being contained within themselves. 

 Secondly, in other instances the ova are developed 

 within the body of the parent, where they lie free, 

 for a time, in some part of the oviduct, with which 

 however they have no organic connection. In this 

 case, as in the former, they derive no nourishment 

 directly from the parent, although some of the fluid 

 with which they are surrounded may be appropriated 



