250 Wisconsin Acackmy of Sciences, Arts, and Letters. 



would be reproduced in precisely the same manner — toes ap- 

 peared in like order, as in the original development. Bat if a 

 branch o£ the gill was removed it was not reproduced, for the 

 reason, it would seem, that the gills were only a temporary organ, 

 only to serve the animal during its embrionic state, while if the 

 feet were to serve the animal through the adult state, their repro- 

 duction became a necessity. Bat, we anticipate, when we clip off 

 a portion of the gills of the menobranch, those portions ampu- 

 tated, that portion was reproduced promptly, so th^t in three 

 weeks the gills were again perfect. The gills being essential to 

 adult life, they were restored. The water puppy is a most beauti- 

 ful object, as it appears in its favorite surroundings, with the long 

 scarlet plumose gills, continually waving backwards and for- 

 ward?. The behavior of the menobranch when confined in an 

 insufficient quantity of water is interesting. As the oxygen be- 

 comes exhausted, the animal rises to the surface, opens the mouth 

 and takes in a portion of air, bubbling it out through the gill 

 openings, thus bringing a portion of air in contact with the gills, 

 or rather by this movement the water is aerated, near the surface, 

 precisely as do fish in similar circumstances. I have frequently 

 seen puddles of water, where the mud fish, melanura limi, 

 abounded, entirely covered with small bubbles formed by these 

 hardy fish in their partially successfal efforts to obtain a saSicient 

 amount of oxygen. 



