of Edinburgh, Session 1885-86. 
931 
Jaworowski on “ Chironomus ” ( Archives Slaves de Biologie , 1886). 
He finds that by rupture of the ovarian membrane the ova fall into 
the body-cavity, and there develop rapidly to form larvae without 
fertilisation. “ The great abundance of nutritive material replaces 
the effect of fertilisation.” 
2. My attention has recently been called by Mr H. B. Brady to 
the phenomenon of “ Dimorphism ” exhibited by certain Fora- 
minifera, and which has been hypothetically interpreted as possibly 
of sexual nature by De la Harpe. An inspection of De la Harpe’s 
figures seems to me to render it clear that this explanation is just 
(the objection of Munier-Chalmas that sex is unknown in Protozoa 
notwithstanding). The form named Nummulites Lamarckii , as 
better grown and less modified, with fewer partitions, and a grand 
logo central , seems to me distinctly the anabolic or female ; the 
other, N. laevigata , since smaller and more modified, the male. 
3. I have finally to record my obligations for much help, both in 
the discussion and preparation of the present paper, to my friend 
Mr J. Arthur Thomson. 
PRIVATE BUSINESS. 
Mr Bobert Kidston, F.G.S., and the Bev. H. G. Bonavia Hunt, 
Mus.B., &c., were balloted for, and declared duly elected Fellows 
of the Society. 
Monday , 19 th July 1886. 
BOBERT GRAY, Esq., Vice-President, in the Chair. 
The following Communications were read : — 
1. On the Colours of Thin Plates. By the Bight Hon. 
Lord Rayleigh. 
2. Ueber algebraische Knoten. Von Dr Franz Meyer 
a. o. Professor in Tubingen. (Plates XXXI., XXXII.) 
Die ersten TJntersuchungen von Herrn Tait fiber “ Knoten,” 
zusammengefasst in der grosseren Arbeit,* Phil. Trans, of Edin- 
* Auf diese beziehen sich die im Texte gemachten Verweisungen. 
