The _Weekly Bulletin_ of San Francisco, 17th May 1893, contains an account of the trapping of a coyote, or prairie wolf, at Punta Banda, San Diego Co., by a _Haliotis Cracherodii_. The coyote had evidently been hunting for a fish breakfast, and finding the _Haliotis_ partially clinging to the rock, had inserted his muzzle underneath to detach it, when the _Haliotis_ instantly closed down upon him and kept him fast prisoner. Rats devour the ponderous Uniones of North America. When _Unio_ moves, the foot projects half an inch or more beyond the valves. If, when in this condition, the valves are tightly pinched, the foot is caught, and if the pinching is continued the animal becomes paralysed and unable to make use of the adductor muscles, and consequently flies open even if the pressure is relaxed. The musk-rat (_Fiber zibethicus_) seizes the _Unio_ in his jaws, and by the time he reaches his hole, the _Unio_ is ready to gape.[134] Rats also eat _Vivipara_, and even _Limnaea_, in every part of the world. Every kind of slug and snail is eaten greedily by blackbirds, thrushes, chaffinches, and in fact by many species of birds. A thrush will very often have a special sacrificial stone, on which he dashes the shells of _Helix aspersa_ and _nemoralis_, holding them by the lip with his beak, until the upper whorls are broken; heaps of empty shells will be found lying about the place of slaughter. The bearded Titmouse (_Parus biarmicus_) consumes quantities of _Succinea putris_ and small _Pupa_, which are swallowed whole and become triturated in the bird’s stomach by the aid of numerous angular fragments of quartz.[135] Frogs and toads are very partial to land Mollusca. A garden attached to the Laboratory of Agricultural Chemistry at Rouen had been abandoned for three years to weeds and slugs. The director introduced 100 toads and 90 frogs, and in less than a month all the slugs were destroyed, and all kinds of vegetables and flowers, whose cultivation had until then been impossible, were enabled to flourish.[136]