228 INTRODUCTION TO ZOOLOOY. 



large canine teeth, but lias obviously not undergone any 

 further subdivision. It has now been ascertained that the 

 coarser portions of the food, from time to time, return 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 Pike, and many other fishes, 

 we have thus an action analogous to that of rumination in 

 the cattle of our pastures.* 



REPRODUCTION. A few fishes are produced 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 male 

 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 continue unhatched in the mud while 

 the pond is dried up; but then vitality remains unimpaired, 

 and the young are produced under the influence of circum- 

 stances favourable to their development when the rainy 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. 



DISTRIBUTION. The researches of naturalists have shown 

 that certain fishes are not merely limited in their range, 

 according to the laws of geographical distribution, but also 

 have certain depths to which they are in a great degree 

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

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



* Owen. 



