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 man- 

 dibles 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 func- 

 tion. They are, further, notoriously variable. Darwin on the whole 

 was disposed to regard them as ornaments. The knowledge there- 

 fore 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 ratber 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. 



We 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 Mena- 

 gerie 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. 



Thd author's views have not been accepted by von Koch, Viguie, 



