330 PKOCEEDINGS OF THE AMERICAN ACADEMY 



but like good neighbors they live peacefully together, passing over 

 each other's domain when going out for food without making any dis- 

 turbance. But whenever an unmated single fish makes its appearance 

 among the nests, he is chased away like an intruding libertine and 

 vagabond. The development of the egg is very rapid. In less than 

 a week the young are hatched, and the parents soon cease to take 

 any further care of them. 



" Pimelodus catus I have had fewer opportunities to watch. How- 

 ever, I have seen them in the spring, which, in the latitude they in- 

 habit, does not fairly set in before the end of May, approach the shores 

 of our ponds, like Pomotis, in pairs, and clear also a space among the 

 low water-grasses, scirpus, and the like, in very shallow water, not 

 more than a foot or so in depth, and deposit its eggs in the same 

 manner as Pomotis, and watch as carefully and vigilantly over its 

 progeny. Yet I have not been able to ascertain how long the period 

 of incubation lasts. But at different times I have seen the young 

 already hatched, still hanging about within the area of the nest, pro- 

 tected by their watchful parent : sometimes the male and female re- 

 maining together with them ; at other times, either one or the other 

 of the old fish keeping watch alone. I have seen larger broods 

 of young, already three fourths of an inch, and even an inch long, 

 remaining together like a flock, around one or the other of the 

 parents ; and sometimes both swimming slowly in the centre or by 

 the side of what, at some distance, would appear like a black cloud 

 rolling slowly through the water in one or another direction, but which, 

 seen more closely, proves to be a flock of young fish. I have ob- 

 served such flocking broods through the whole month of June, and 

 noticed that in each the young were of larger and larger size in the 

 latter part of that month, until they swim more loosely, and finally 

 disperse half together ; the parents standing nearer the flock, or even 

 in its centre, in proportion as the fish are smaller. When watching 

 over the eggs which are not yet hatched, or when following the young 

 brood, the old fish seem very solicitous for the safety of their progeny, 

 and drive away with great fierceness any approaching enemy. I have 

 even seen one dart at a little hand-net which I was dipping in the 

 water, to secure the young which were still hovering over their nest. 



" Having thus far become familiar with the mode of reproduction 

 of Pimelodus, the statements of Aristotle relating to the Glanis of 

 Greece, which is another representative of the same family of Silu- 



