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Show 112 TIABITS OF WORMS. CHAP. II. unusual thickness. In this case the worms, judging from the castings, had pushed the cinclers away on all sides and had not swallowed any of them. In another place, burrows similarly lined, passed through a layer of coarse coal-cinders, 3~ inches in thickness. We thus see that the burrows are not mere excavations, but may rather be compared with tunnels lined with cement. 1'he n1ouths of the burrow are in addition often lined with leaves; and this is an instinct distinct from that of plugging them up, and does not appear to have been hitherto noticed. Many leaves of the Scotch-fir or pine (Pinus sylvestris) were given to worms kept in confinmnent in two pots; and wlJen after several weeks the earth was carefully broken up, the upper parts of three oblique burrows were found surrounded for lengths of 7, 4, and 3k inches with pine-leaves, together with fragments of other leaves which had been given the worms as food. Glass beads and bits of tile, which had been strewed on the surface of the soil, were stuck into the interstices between the pine-leaves; and these interstices were likewise plasterecl with the CrrAP. II. CONSTRUCTION OF 'J.1JIEm BUHROWS. 113 viscid castings voided by the worm . The structures thus formed cohered so wclJ, that I succeeded in removing one whh only a littl , earth adhering to it. It consisted of a slio-htly curved cylindrical case, the interior of which could be seen through holes in the . ides and at either end. The pine-leaves hacl all been drawn in by their bases; and the sharp poiut of the needles had been pressed into the lining of voided earth. Ifacl this not been effectually done, the sharp points would have prevented the retreat of the worms into tl1eir burrows; and these structures would have resembled traps armed with eonvero-inO' b b points of wire, rendering the ingress of an animal easy and its egress difficult or impossible. The skill shown by these worm~ is notewortl1y and is the more rcmarkaLle, a~ the Scotch pine is not a native of this distric:t. .After having examined tl1ese burrows made by worms in confinement, I Jooke l at tho~e in a flower-bed near ·ome Scotch pin es. These had all been plugged up in the ordinary manner with the leave of this tree, dr.av.tn iu for a length of from I to 1 ~ inch; but tlw mouths of many of them were likewise lined I |
