Female genital mutilation in Africa persists despite modernization, public education, and legal prohibition. Female footbinding in China lasted for 1,000 years but ended in a single generation. 1 show that each practice is a self-enforcing convention, in Schelling's (1960) sense, maintained by interdependent expectations on the marriage market. Each practice originated under conditions of extreme resource polygyny as a means of enforcing the imperial male's exclusive sexual access to his female consorts. Extreme polygyny also caused a competitive upward flow of women and a downward flow of conjugal practices, accounting for diffusion of the practices. A Schelling coordination diagram explains how the three methods of the Chinese campaign to abolish footbinding succeeded in bringing it to a quick end. The pivotal innovation was to form associations of parents who pledged not to footbind their daughters nor let their sons marry footbound women. The "convention" hypothesis predicts that pronzotion of such pledge associations would help bring female genital mutilation to an end.

Dreissena polymorpha, a bivalve mollusc endemic to Europe, has established a population in Lakes St. Clair and Erie, likely as a result of ballast water discharge. Allozyme studies showed that the Lake St. Clair population was polymorphic at 73.9% of the loci examined and that individual heterozygosities averaged 31.6%. This high level of genotypic diversity indicated that the population was founded from a substantial number of individuals and did not undergo a bottleneck subsequent to founding. The population is reproducing with peak densities in excess of 200 individuals∙m−2. Juvenile settlement occurs in late July and August with veliger larvae preferentially settling on the shells of live mussels. The species appears likely to become a dominant member of the shallow water benthos throughout the lower Great Lakes.

This is the first American Fisheries Society conservation assessment of freshwater gastropods (snails) from Canada and the United States by the Gastropod Subcommittee (Endangered Species Committee). This review covers 703 species representing 16 families and 93 genera, of which 67 species are considered extinct, or possibly extinct, 278 are endangered, 102 are threatened, 73 are vulnerable, 157 are currently stable, and 26 species have uncertain taxonomic status. Of the entire fauna, 74% of gastropods are imperiled (vulnerable, threatened, endangered) or extinct, which exceeds imperilment levels in fishes (39%) and crayfishes (48%) but is similar to that of mussels (72%). Comparison of modern to background extinction rates reveals that gastropods have the highest modern extinction rate yet observed, 9,539 times greater than background rates. Gastropods are highly susceptible to habitat loss and degradation, particularly narrow endemics restricted to a single spring or short stream reaches. Compilation of this review was hampered by a paucity of current distributional information and taxonomic uncertainties. Although research on several fronts including basic biology, physiology, conservation strategies, life history, and ecology are needed, systematics and curation of museum collections and databases coupled with comprehensive status surveys (geographic limits, threat identification) are priorities.

Is there a public good? A prevalent view in political science is that democracy is unavoidably chaotic, arbitrary, meaningless, and impossible. Such scepticism began with Condorcet in the eighteenth century, and continued most notably with Arrow and Riker in the twentieth century. In this powerful book, Gerry Mackie confronts and subdues these long-standing doubts about democratic governance. Problems of cycling, agenda control, strategic voting, and dimensional manipulation are not sufficiently harmful, frequent, or irremediable, he argues, to be of normative concern. Mackie also examines every serious empirical illustration of cycling and instability, including Riker's famous argument that the US Civil War was due to arbitrary dimensional manipulation. Almost every empirical claim is erroneous, and none is normatively troubling, Mackie says. This spirited defence of democratic institutions should prove both provocative and influential.

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The zebra mussel, Dreissena polymorpha, is a new exotic species that was introduced into the Great Lakes as early as the fall of 1985 . It differs markedly from native species of bivalves in its : (i) shell form ;(ii) mode of life ; (iii) reproductive potential ; (iv) larval life cycle ; (v) population dynamics ; (vi) distribution, (vii) dispersal mechanisms ; (viii) physiology ; (ix) potential impact on the ecosystem ; and (x) impact on society and the economy . In body form, it has an anterior umbone, a flat ventral surface with permanent aperature for the byssal apparatus and a shape that together make the animal well adapted for life on a hard surface . The shell has a zebra-stripe pattern, a heteromyarian muscle condition and lacks hinge teeth which make it easily identifiable from native bivalves . The zebra mussel is strongly byssate and has an epifaunal mode of life not seen in native bivalves . The species is dioecious and has external fertilization, the eggs developing into pelagic veligers which remains planktonic for approximately 4 weeks . Gametogenesis begins in late winter to early spring, veligers appear in the water column in late May to early June and disappear in mid to late October in Lake St . Clair . Adults live for about 2 years and have very rapid growth rates . Maximum shell lengths average 2 .3 to 2 .5 cm . Standing crops as high as 200 000 m-2 are present in the 1-m depths of the Ontario shores . Infestations may be interfering with the normal metabolism of native unionid clams and there is potential of the unionid clam populations being reduced or even eliminated from Lake St . Clair .

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