I believe that I have not yet acknowledged the receipt of your notes, and a five dollar bill. I am very glad that the fishes afforded Mr. Agassiz so much pleasure. I could easily have obtained more specimens of the Sternothaerus odoratus; they are quite numerous here. I will send more of them erelong. Snapping turtles are perhaps as frequently met with in our muddy river as anything, but they are not always to be had when wanted. It is now rather late in the season for them. As no one makes a business of seeking them, and they are valued for soups, science may be forestalled by appetite in this market, and it will be necessary to bid pretty high to induce persons to obtain or preserve them. I think that from seventy-five cents to a dollar apiece would secure all that are in any case to be had, and will set this price upon their heads, if the treasury of science is full enough to warrant it.You will excuse me for taking toll in the shape of some, it may be, impertinent and unscientific inquiries. There are found in the waters of the Concord, so far as I know, the following kinds of fishes:—

  Pickerel. Besides the common, fishermen distinguish the Brook, or Grass Pickerel, which bites differently, and has a shorter snout. Those caught in Walden, hard by my house, are easily distinguished from those caught in the river, being much heavier in proportion to their size, stouter, firmer fleshed, and lighter colored. The little pickerel which I sent last, jumped into the boat in its fright.

  Pouts. Those in the pond are of different appearance from those that I have sent.

  Breams. Some more green, others more brown.

  Suckers. The horned, which I sent first, and the black. I am not sure whether the Common or Boston sucker is found here. Are the three which I sent last, which were speared in the river, identical with the three black suckers, taken by hand in the brook, which I sent before? I have never examined them minutely.

  Perch. The river perch, of which I sent five specimens in the box, are darker colored than those found in the pond. There are myriads of small ones in the latter place, and but few large ones. I have counted ten transverse bands on some of the smaller.

  Lampreys. Very scarce since the dams at Lowell and Billerica were built.

  Shiners. Leuciscus chrysoleucas, silver and golden.

  What is the difference?

  Roach or Chiverin, Leuciscus pulchellus, argenteus, or what not. The white and the red. The former described by [David H.] Storer, but the latter, which deserves distinct notice, not described, to my knowledge. Are the minnows (called here dace), of which I sent three live specimens, I believe, one larger and two smaller, the young of the species?

  Trout. Of different appearance in different brooks in this neighborhood.

  Eels.

  Red-finned Minnows, of which I sent you a dozen alive. I have never recognized them in any books. Have they any scientific name?

  If convenient, will you let Dr. Storer see these brook minnows? There is also a kind of dace or fresh-water smelt in the pond, which is, perhaps, distinct from any of the above. What of the above does M. Agassiz particularly wish to see? Does he want more specimens of kinds which I have already sent? There are also minks, muskrats, frogs, lizards, tortoise, snakes, caddice-worms, leeches, muscles, etc., or rather, here they are. The funds which you sent me are nearly exhausted. Most fishes can now be taken with the hook, and it will cost but little trouble or money to obtain them. The snapping turtles will be the main expense. I should think that five dollars more, at least, might be profitably expended.