In planning for the closing of portions of rivers for periods of years consideration should be given to community needs as well as to general economic and biological conditions. On the one hand, the closure will be more effective in result, as well as easier of enforcement, if the regions of closure are made very large; while, on the other hand, making the closed regions smaller might cause less economic inconvenience. If, for example, the entire Illinois River should be closed to mussel fishery for a period of several years, there might be a substantial uncompensated loss to some communities, where there are factories employing labor to cut shells derived from that river. On the other hand, should we divide the river up into small sections of 2 or 3 miles in extent, some of which would be open while others would be closed under the law, it is apparent that such a plan would be almost impossible of enforcement. To prevent shelling from being carried on in all these little, closed areas would require a force of wardens and an expense entirely incommensurate with the object to be gained. It is held advisable to divide a river within a single State into some four or six sections for the purpose of establishing closed regions. One-half--that is, two or three--of these sections, taken in alternation, could be ordered closed for a period of five years, during which no mussel fishing at all should be allowed in the closed sections, although it would be regularly prosecuted in the alternate portions of the stream. It would be convenient to break a river at points where there was a substantial community interest in the shelling. PRACTICABLE DIVISION OF RIVER SYSTEMS ILLUSTRATED. For example, let us apply this method of dividing a stream to the White and Black Rivers in Arkansas. Starting from the head-waters of the Black River, we find the first center of economic interest at Black Rock, another on the White River at Newport, and a third at Clarendon. Now, the river might properly be broken at these points, forming four main sections. The fishery might then be entirely prohibited for several years from the mouth of the river to Clarendon, while permitted from Clarendon to Newport, and again prohibited from Newport northward to Black Rock on the Black River, and to Batesville or other suitable point on the upper White, while permitted from Black Rock and Batesville northward on all the tributaries. We would have the river system divided into four sections, which would be probably as nearly equivalent as could be expected. Furthermore, none of the three towns mentioned would be cut off from the local supply of shells, except in one direction.