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Show 594 DR. S. J. HICKSON ON ALCYONARIA STOLONIFERA. [DeC. 6, very scarce, but in the Stag-beetle it is the high male that is common while in most places the low male is absent or scarce. In this case, and in that of X. gideon also, the ratio of the mandibles or horns to the total length is higher in the high males than in the low males; or, in other words, though the body of a high male is larger than that of a low male, the horns of the high male are still larger in proportion to the body than those of the low male. In conclusion we would call attention to the fact that fantastic secondary sexual horns present one of the most difficult problems in Evolution, for as to their modes of origin even guesses can scarcely be made. To their production a considerable expenditure of energy is clearly needed, and yet in many cases they have no obvious function. They are, further, notoriously variable. Darwin on the whole was disposed to regard them as ornaments. The knowledge therefore that variation in the degree of development of these structures may be discontinuous is a material assistance to the formation of any conception as to the manner of their origin. The question may be asked, does the dimorphism of which cases have now been given represent the beginning of a division into two species, or rather a division which might be accentuated so as to lead to such division ? To this question we have no answer to make, but such a possibility may well be remembered. W e must express our thanks to Messrs Macmillan for their kindness in allowing us to use the drawings of figs. 1-4, which have been prepared by them in illustration of a forthcoming book by one of us on the subject of Variation. December 6, 1892. Dr. St. George Mivart, F.R.S., Vice-President, in the Chair. The Secretary read the following report on the additions to the Society's Menagerie during the month of November 1892:- The total number of registered additions to the Society's Menagerie during the month of November were 144, of which 94 were by presentation, 7 by birth, 39 by purchase, 2 by exchange, and 2 on deposit. The total number of departures during the same period, by death and removals, was 82. Dr. S. J. Hickson, F.Z.S., read a paper entitled " A Revision of the Genera of the Alcyonaria Stolonifera, with a Description of one new Genus and several new Species," of which the following is an abstract:- In a communication made to the Royal Society in 1883, the author proposed to separate those Alcyonarians in which the polyps spring independently from a creeping stolon into a suborder, the Stolonifera. The author's views have not been accepted by von Koch, Viguie, |