38 
Bedlow’s Island to far above Tappan, the gil-nets obstruct tbeir passage in the chan¬ 
nel. The porpoise, the fish-hawk, and man, pursue them from their first advent on 
the coast, until the act of spawning in the fresh water has reduced them to skeletons. 
Yet periodically and annually they revisit the troubled waters to perpetuate their 
species. 
The winter abode of the shad is as uncertain and as little known as the aphelion 
of an unscanned comet. They strike the coast north of Florida, and enter the prin¬ 
cipal fresh water rivers between Florida and Massachusetts. Their progress is al¬ 
ways northerly. They enter the Savannah, the Potomac, the Delaware, the Hudson, 
and the Connecticut Rivers consecutively,—the collateral or smaller streams, like the 
Hackensack or Passaic, receiving a due portion of visitors. They strike the Hudson 
in shoals of greatest force about the 21st day of April—seldom more than three days 
later or in advance of that time. They soon lose a portion of their scales in the ri¬ 
ver ; but the fact of their entering in compact shoals wdth perfect scales, has induced 
a belief that they could not have been many hours subject to agitation from porpoises 
or hawks. They probably live and grow during the winter in deep cavities near the 
coast. We may suppose that previous to the time for spawning, the shad has a very 
small sound or air bladder, which would enable them to sink to a great depth, say 
one thousand feet, Which would give a pressure or density of thirty atmospheres, equi¬ 
valent to four hundred and fifty pounds for every square inch—a pressure which the 
porpoise could not sustain. The maturing of the spawn may increase the amount of 
air in the sound, and enable the fish to rise at the proper time for ascending the fresh 
water streams. 
The shad that enter the rivers, are found returning to the sea in midsummer in 
a very poor condition. The young shad descend the streams in the fall- A small 
fish about one or two inches long, and resembling smelt, enter the rivers in great 
abundance at the same time as the shad, which feed and fatten on them. 
It is probable that the shad which enter different rivers are different varieties. 
A difference is discernablc as w ell between the shad of different rivers, as between the 
different shoals which enter the same river. The shad which enter the Hudson, may, 
for example, be those only that were spawned in that river, and each variety or tribe 
may have its separate winter cavity in the ocean, near the mouth of the river in which 
it was spawned. 
Flexible Corallines, under the general division Zoophytes, were little known un¬ 
til about the middle of the eighteenth century, 100 years ago, when Linnaeus, Spal¬ 
lanzani, Fallas, Muller, Ellis, and others, published the results of their valuable re¬ 
searches in Natural History. Cuvier, Lamarck, Lamouroux, Latreille, Fleming 
Johnston, and many others of equal merit in the present century, have made large 
contributions to our knowledge of Zoophytes. Unimportant differences occur in the 
classifications of those authors, and differences in opinions of some importance, on 
the animal or vegetable nature of the several orders, is discussed with more or less 
ability by all of them. 
