bo INTRODUCTION. 



adopt the words of Mr. Walcott, the original dis- 

 coverer of this interesting fact in the Pipe-fish, — 

 " The male differs from the female in the belly, 

 from the vent to the tail-fin being much broader, 

 and in having, for about two-thirds of its length, 

 two soft flaps, which fold together, and form a 

 false belly or pouch. They breed in the summer ; 

 the females casting their roe into the pouch of the 

 male." Here the ova are nurtured, and the young, 

 when ready, escape from the capsules. This re- 

 markable structure in the Hippocampus had not 

 escaped the keen eye of John Hunter; and some 

 specimens still exist in the Museum of the London 

 College of Surgeons, which had been exposed, and 

 partly examined by this great anatomist. Even 

 when able to swim about, the young pipe-fish seek 

 the protection afforded by this curious contrivance. 

 " I have been assured," says Mr. Yarrell, " that if 

 the young were shaken out of the pouch into the 

 water over the side of a boat, they did not swim 

 away; but when the parent fish was held in the 

 water, in a favourable position, the young would 

 again enter the pouch." M. Risso particularly no- 

 tices the great attachment of the adult Pipe-fish to 

 its young, and suggests, that this pouch is the place 

 of shelter whither the latter retreat in case of 

 danger. 



To one other remarkable variety in the develop- 

 ment of this class we must advert. The singular 

 peculiarity of the Pijya, or Surinam toad, must be 



