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SynopsisOutstanding structural features related to habits of life in the chydorid cladoceranEurycercus lamellatusare described. Crawling is as important as swimming in this deposit-feeding species. The nature of the food, its collection and subsequent manipulation, are described. Both cephalic and trunk appendages are involved in this process. Their structure and mode of action are described and illustrated in detail. Many hitherto unknown structural features are described and the functional significance of these and other morphological peculiarities is explained.

Pinus contorta var. latifolia and Picea engelmannii recruitment and mortality were reconstructed in 13 lower subalpine stands from age—height curves of live trees, saplings, and seedlings, and from cross—dated dead standing, fallen, and buried stems. Bole decomposition rates indicated the populations could only be reconstructed without bias during approximately the second half of a stand's history, irrespective of the stand's age. All stands traced similar recruitment and mortality patterns for the overlapping parts of their histories. Fire and understory regeneration cohorts were recognized based on risk histories. The lodgepole pine fire cohort established in the first decade after fire. Its mortality was high but decreasing in the first 10 yr, low and constant until thinning began at °25 yr, and increasing for the next °200 yr. The understory cohort recruitment started °15 yr after fire and its mortality was high, and constant with <0.5% chance of reaching the canopy. As with pine, Engelmann spruce recruited mostly in the first decade after fire, followed by low and sporadic recruitment for the next 200 yr. The mortalities of the Engelmann spruce fire and understory cohorts were constant, with the understory mortality slightly higher than the mortality of the fire cohort. As with pine, the chances of the understory reaching the canopy were small. Since the recruitment of both pine and spruce does not compensate for their mortality, the population is not self—reproducing. The population is not transient, however, because the calculated fire frequency of the area ensures burning within the life—span of the fire cohort, allowing regeneration. Consequently the long—term population dynamics of pine and spruce appear to be controlled by fire frequency.

The first satisfactory groupings of the components of the Branchiopoda (Crustacea) were those of G. 0. Sars, whose successive refinements, as modified by Calman in a much used work, received wide acceptance. Thesr schemes, and the more important of the subsequently suggested changes, are listrd and tabulated. The Branchiopoda is a morphologically heterogeneous group whose component subgloups share a constellation of primitive features. It is also ancient, with representatives known from as Far back as the Devonian, and probably originated in pre-Devonian timrs, yrt still has many extant, sometimes highly successful, representatives. Such a situation presents difficulties to the would-be classifier. A new scheme is proposed which involves the elevation of four lower categories among the so-called Cladocera to ordinal rank. Two cunchostracan taxa are also given ordinal status. The ten constituent orders now recognized within the Branchiopoda are defined in more detail than hitherto as a working basis for future investigations.

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