United States or Myanmar ? Vote for the TOP Country of the Week !
In a sinistral Flat-fish, whether it is normally sinistral like the Turbot or abnormally like a 'reversed' Flounder, the viscera are in the same position as in a dextral specimen: the liver is on the left side, the coils of the intestine on the right.
On the other hand, the transportal of the lower eye of a flat-fish to the upper side of the head, and the formation of a prehensile tail, may be attributed almost wholly to continued use, together with inheritance.
The street-hawkers who had clubbed together to buy lots of herrings and small flat-fish were dividing them on the pavement.
Such specimens have been called ambicolorate, but it is an important fact that they are also ambiarmate that is to say, the scales or tubercles which in the normal Flat-fish are considerably reduced or absent on the lower side, in these abnormal specimens are developed on the lower side almost as much as on the tipper.
As compared with the normal Flat-fish they arise by a discontinuous variation, they are mutations, whereas the normal Flat-fish as compared with its symmetrical ancestor arises by a continuous change. In order to make my meaning clear I must point out that I have been using the word continuous in a different sense from that in which it is used by other biologists, Bateson for example.
One of the chief differences between structural features and correlations which are adaptive from those which are not is the process of metamorphosis, where we see the structure changing in the individual life history as the mode of life changes. The egg of the Flat-fish develops into a symmetrical pelagic larva similar to that of many other marine fishes.
"Oh! the fishermen will give me more." "The fishermen will give you a couple of stale flat-fish, to take home to your mother." "Well, I'll try that," said I, going. "Not so fast, Jack, not so fast; if I make a penny by you one day, I suppose, to keep your custom, I must lose something by you the next. Now, I'll give you sixpence; and how I'm to get my money back I don't know."
We may also attribute to the inherited effects of use the fact of the mouth in several kinds of flat-fish being bent towards the lower surface, with the jaw bones stronger and more effective on this, the eyeless side of the head, than on the other, for the sake, as Dr. Traquair supposes, of feeding with ease on the ground.
Some were running races on horseback; some playing at football; some were catching eels and flat-fish; and others plunging and frolicking in the waves. Captain Church was uncertain whether they were enemies or friends. With characteristic sagacity and intrepidity, he retired some distance into a thicket, and then hallooed to them.
From the colourless state of the ventral surface of most fishes and of many other animals, we may reasonably suppose that the absence of colour in flat-fish on the side, whether it be the right or left, which is under-most, is due to the exclusion of light.
Word Of The Day