Frequency of "Cell-Lethals" among Lethals Obtained at Random in the X-Chromosome of Drosophila Melanogaster.

84 per cent albite and we know enough of relations in our general system (Fig. 1) to be able to say that the conditions are similar in mixtures with an excess of silica (simplified fayalite-rhyolites) and also in those with a deficiency of silica (simplified fayalite-phonolites). While we have made only a first step in the investigation of these extreme liquids it is plain from the results of this study that the moderate content of iron silicates in rocks rich in alkali feldspars cannot be urged as a feature militating against the acceptance of the rocks as substantially representative of the residual liquids from the fractional-crystallion of more complex "basic" magmas.