Liz CoMPARATIVE ARCHA2OLOGY. 
wood, two to three feet in length, and perforated in the middle 
by an elongated aperture (Figs. 1 and 2). Into this aperture 
4 valve, movable on projecting pivots at one side, was ad- 
justed, so that when the aperture was open the valve stood 
at right angles to the surface of the machine. Over the valve 
an elastic rod stretched the whole length of the body, and so 
arranged as to have a to and fro movement at each end. When 
the valve was open the rod was bent upwards, and to keep 
it in this position a bit of stick was inserted to which the bait 
Fig. 2.—Wooden Trap (Laibach), Bivalvular. 
was attached. When an animal pulled the bait the bit stick 
gave way, and the valve closed with a bang, caused by the 
pressure of the elastic rod, and thus caught the otter, beaver, 
or duck by the neck. Looking at the modus operandi of these 
ingenious contrivances, I find that they are divisible into two 
categories, according as the aperture is fitted with one (Fig. 1) 
or two valves (Fig. 2), the latter being simply a reduplication 
of the parts of the former. It is somewhat significant to find 
that all the traps hitherto discovered within the British Isles, 
eleven in number, were univalvular, while on the continent 
only one, now preserved in the Museum of Stettin, belonged 
to this category. 
