212 INTRODUCTION TO ZOOLOGY. 



large canine teeth, but has obviously not undergone am' 

 further subdivision. It has now been ascertained that the 

 coarser portions of the food, from time to time, retui-n into 

 the oesophagus, and are brought within the sphere of the 

 teeth with which the pharynx is furnished ; and, after being 

 there carded and comminuted, are again swallowed. In the 

 Carp, the Tench, the Eel, the Pil^e, and many other fishes, we 

 have thus an action analogous to that of rumination in the 

 cattle of our pastures.* 



Repeodtjction. — A few fishes are brought forth alive — as, 

 for example, the young of the Viviparous Blenny ; but such 

 instances are rare ; and, as a general rule, it may be stated 

 that fishes are produced from eggs deposited by the female, 

 and fertilized by the male. The lobes containing the ova are 

 those to which we are accustomed to give the name of " pea " 

 or "roe," and the corresponding but softer lobes in the m.ale 

 fish, are those which are equally well known as the "milt." 

 It has been found by experiment, that when the spawn of 

 both sexes has been taken from dead fishes and mixed 

 together, the ova, placed under water and kept in a proper 

 situation, will produce young. This fact may serve, as Mr. 

 Yarrell remarks, to explain how it is that ponds in the East 

 Indies, which have become perfectly dry and the mud hard, 

 have been found, after the rainy season, with fishes in them, 

 although there did not exist any apparent means by which 

 fish could be admitted. The impregnated ova of the fish 

 of one rainy season continued unhatched in the mud while 

 the pond is dried up ; but then vitality remains unimpaired 

 and the young are produced under the influence of cu'cum- 

 stances favourable to their development when the rain}^ season 

 has again arrived. We can thus explain, by the operation of 

 natural causes, what was regarded as a puzzling phenomenon, 

 for the solution of which many hypotheses have been framed, 

 alike destitute of any solid foundation. 



Disteibution. — The researches of naturalists have shown 

 that certain fishes are not merely limited in their range, ac- 

 cording to the laws of geographical distribution, but also 

 have depths to which they are in a great degree re- 

 stricted. Hence, some are most usually found at or near the 

 surface; some ai'e ground-feeders, and are taken at consider- 



• Owen. 



