| Summary: | Procedures to reduce errors in Coulter analyses - In counts of suspensions of algae and inert particles made with a negative external electrode (EE), neither total number of particles per unit volume of suspension nor mean cell or particle volume (MCV) ever changed. In contrast, a count made with a positive EE exhibited a substantial change in MCV. A review of published investigations of damage to red blood corpuscles caused by a count suggests that they are affected in a similar way. Function of the gizzard in Bryozoa - Five gizzard-bearers frequently displayed significantly greater ability to break diatom frustules, when compared with two other bryozoans. The species lacking a gizzard have good ability to separate valves of some diatoms frustules, even to the extent of equalling the percentage broken by the gizzard of <i>Bowerbankia</i>. However, bryozoans that possess a gizzard are small, too small to ingest a majority of the common diatoms. Selection of food by two marine bryozoans - The preferences of <i>Electra pilosa</i> and <i>Flustrellidra hispida</i> have been investigated. <i>E. pilosa</i>, offered mixtures of algae and pollen, did not distinguish between pollen and algal cells but preferentially selected foods of 15-40 um diameter. <i>E. pilosa</i> appears able to select particles with regard to size but not taste, and preferences are affected by total but not relative food concentration. <i>E. pilosa</i> and <i>F. hispida</i> have lophophores of greatly different size, but preferentially selected similar size categories from seston. These were those sizes most abundant in local seawater samples. Optimal design of the bryozoan lophophore - The lateral cilia of <i>Flustrellidra hispida</i> close the intertentacular gap over the proximal 30%, or less, of the length of the gap. A method was developed to study optimal design, and used to determine which characteristics of funnel morphology are optimized by natural selection.
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