Wood frog pollywogs.

April 11. 

P. M. – To Lee's Cliff. 

The black spheres (rather dark brown) in the Rana sylvatica spawn by Hubbard's Grove have now opened and flatted out into a rude broad pollywog form. (This was an early specimen.) 

Yesterday saw moles working in a meadow, throwing up heaps. 

I notice at the Conantum house, of which only the chimney and frame now stand, a triangular mass of rubbish, more than half a bushel, resting on the great mantel-tree against an angle in the chimney. It being mixed with clay, I at first thought it a mass of clay and straw mortar, to fill up with, but, looking further, I found it composed of corn-cobs, etc., and the excrement probably of rats,  and of pure clay, looking like the cells of an insect. Either the wharf rat or this country rat. They had anciently chosen this warm place for their nest and carried a great store of eatables thither, and the clay of the chimney, washing down, had incrusted the whole mass over. 

So this was an old rats’ nest as well as human nest, and so it is with every old house. The rats’ nest may have been a hundred and fifty years old. Wherever you see an old house, there look for an old rats’ nest. In hard times they had, apparently, been compelled to eat the clay, or it may be that they love it. It is a wonder they had not set the house on fire with their nest. 

Conant says this house was built by Rufus Hosmer's great-grandfather. 

Slippery elm. 

Crowfoot (Ranunculus fascicularis) at Lee's since the 6th, apparently a day or two before this. 

Mouse-ear, not yet. 

What that large frog, bullfrog-like but with brown spots on a dirty-white throat, in a pool on Conantum? 

See thimble-berry and rose bush leafing under the rocks.

H. D. Thoreau, Journal, April 11, 1858

The black spheres (rather dark brown) in the Rana sylvatica spawn. See April 4, 1857 "Caught a croaking frog . . .Nearby was its spawn, in very handsome spherical masses of transparent jelly, two and a half to three inches in diameter, suspended near the surface of some weed, as goldenrod or aster, and consisting of globules about a third of an inch in diameter, with a black or dark centre as big as a large shot. Only these black centres were visible at a little distance in the water, and so much the more surprising and interesting is the translucent jelly when you lift it to the light."); April 4, 1858 ("Go to the cold pond-hole south of J. P. Brown’s, to hear the croaking frogs.. ..[T]hey have dropped their spawn on the twigs.. . .. I see one or two pairs coupled, now sinking, now rising to the surface. The upper one, a male, quite dark brown and considerably smaller than the female, which is reddish--such part of her as I can see--and has quite distinct dark bars on its posterior extremities, while I cannot discern any on the male. .. . To my surprise the female was the ordinary light-reddish-brown wood frog (R. sylvatica), with legs distinctly barred with dark, while the male, whose note alone I have heard, methinks, was not only much smaller, but of a totally different color, a dark brown above with dark-slate colored sides, and the yet darker bars on its posterior extremities a. . . There was a good deal of spawn firmly attached to the brush close to the surface, and, as usual, in some lights you could not see the jelly, only the core.")