In most large fisheries for certain species numerous changes occur at intervals in the apparatus used, owing to changed conditions, etc., but in the lobster industry changes have been few, and at an early period the fishermen fixed upon a uniform apparatus, which has been in use ever since with but slight modifications, and these generally only temporary. The earliest form of apparatus used to any considerable extent was the hoop net. This consisted generally of a hoop or ring of about 1/2-inch round iron, or a wooden hogshead hoop, from 2-1/2 to 3 feet or more in diameter. To this hoop was attached a net bag with a depth of 18 to 24 inches as a bottom, while two wooden half hoops were bent above it, crossing at right angles in the center about 12 or 15 inches above the plane of the hoop. Sometimes these half hoops were replaced by short cords. The bait was suspended from the point of crossing of the two wooden hoops and the line for raising and lowering the pots was attached at the same place. As there was no way of closing the mouth of the pot after a lobster had entered, these nets had to be constantly watched, the lobster being in the habit of retiring after he had finished his repast. In using these the fisherman would generally go out in the evening and at short intervals he would haul in his nets and remove whatever lobsters they might contain. The constant attention necessary in attending to these hoop nets led the fishermen to devise an apparatus which would hold the lobsters after once entering and would require only occasional visits, and "lath pots" were found to fulfill all requirements. They acquire the name from the use of common laths in their construction. They are usually about 4 feet in length, with a width of about 2 feet, a height of 18 inches, and in Maine are usually of semicylindrical form. The following description of this apparatus is from the Fishery Industries of the United States, sec. v, vol. 11, p. 666: