562 LOB-WOEM LOCK our species is distinct from H. gammams (Milne- Edwards) of Europe, and grows to a larger size. Their food is entirely animal. They are caught in baskets or traps, with a concave netting at each end having a hole in the centre, and bait- ed with dead fish or any garbage ; they can enter easily, but their expanded claws prevent egress, on the principle of the common wire rat trap. These traps, sunk to the bottom in deep water, and their places marked by wooden floats, are raised every day or two, and their contents removed; to prevent their injuring each other, a wooden plug is driven into the joint of the movable thumb, which keeps the claw shut, and they are then transferred to a large floating car, in which they will live many days, until they are wanted for market. The limit of salable size in Massachusetts is at all seasons 10| inches. It would be impossible to estimate the number consumed annually in the fresh state, but it must be counted by hundreds of thousands ; as the price varies from 3 to 6 cents a pound, at the lowest, it will be seen that the lobster fishery is a source of a very great revenue to New England, which is their principal habitat and market. The sliortest way of killing them is breaking off the rostrum. They are considered as good only for bait while undergoing the change of the shell ; no part is poisonous, though the cartilaginous stomach or "lady " is so tough that no one would think of eating it ; like other crustaceans and shell fish, they sometimes cause eruptions of the skin in hot weather and in susceptible constitutions ; the unimpregnated eggs, of a fine red color, commonly called " coral," are considered a delicacy. For further details on the habits of the lobster, see Prof. Verrill's " Report on the Invertebrate Animals of Vineyard Sound and adjacent Waters" (Washington, 1873). The genus palinuruB (Fabr.), or spiny lobster, of the European seas, grows to a weight of 15 or 20 Ibs.; the shell is hard and spiny, the antennae are much longer than the body, and the claws are very small ; it is much esteemed as food, and was prized by the ancient Eo- mans, who called it locusta. LOB-WORM, a common species of the dorsi- branchiate annelids, the errantes of some au- thors, and the genus arenicola. The first name Lob- Worm, is derived from the situation of the gills or branchiae, arranged in tufts along the sides of the back ; and the second from the fact that they lead a free life, being never confined in FIG. 1. tubes. They burrow in the sand and under stones, moving by means of lateral unjointed appendages, provided with bristles. The mouth is on the under side of the head, which has eyes and unjointed feeders. The sexes are separate. The A. piscatorum of the English coasts is used as bait. (See ANNELIDA.) LOCK, a fastening for doors, boxes, &c., de- signed not to be opened except by an instru- ment called a key especially adapted to the lock, or by manipulating some secret arrange- ment of bolts and pins. The Egyptians used locks of a simple construction about '4,000 years ago, and more perfectly constructed locks have been used by the Chinese for cen- turies. The Chinese lock is furnished with parts which are called tumblers, and resemble the modern tumbler lock. The locks in use in England about 100 years ago are still found in that coun- try and in the United States to a limited ex- tent on common doors and boxes. They are called spring locks, and their general con- struction is represented in fig. 1. The bolt b passes through a rectangular hole in each end of the lock, and is held either out or in by two notches c e, which are pressed against the edge of the hole by the spring a. The face of the key is seen to lie in a semicircular notch in the lower edge of the bolt, which is by that means moved backward and forward. A number of circular partitions, called wards, whose edges are seen sur- rounding the shaft of the key, prevent any key which has not cor- responding open spa- ces from being used. The ordinary key may have the form shown in fig. 2, but it is evi- dent that it will answer the purpose of open- ing the lock as well if the parts are cut away, as in fig. 3 ; this is called a skeleton key, and is in common use among thieves in picking locks. The common tumbler lock, which has only been in use in Europe and this country during the last 100 years, is represented in its simplest form in fig. 4. The bolt 5 I is moved out and in by the key in the same manner as in the spring lock, but it is held from moving by processes or projec- tions in a tumbler, , which are thrown by a spring into notches in the upper edge of the bolt. This tumbler has to be raised by the key before the bolt can be moved. Bar- ren's lock, patented in 1778, is so contrived that the processes in the bolt have to be FIG. 2. FIG. FIG. 4.
