76 Proceedings of the Royal Society 
was in part due to the detention of his papers in Scotland until 
after the peace of 1815. 
I have been indebted for some valuable information respecting 
M. Necker’s earlier history to the kind communications of Pro- 
fessor Alfred G-autier, a distant connection and attached friend of 
the subject of this biography. 
2. On the Structure and Optical Phenomenon of Decom- 
pressed Glass. By Principal Sir David Brewster. 
3. Notes on the Anatomy of the Genus Firola. By John 
Denis Macdonald, E.N.,F.E.S., Surgeon of H.M.S. “Icarus.” 
Communicated by Professor Maclagan. 
These notes are intended to form an appendix to the author’s 
paper on the anatomy and classification of the Heteropoda, read 
before the Society last session. He finds the relationship between 
Firola and Firoloides even closer than he had supposed, and that, 
with the exception of gills in the former genus, nearly every ana- 
tomical point occurring in one, may be distinctly traced out in 
the other, only differing in relative characters. The author de- 
scribes in detail the anatomy of Firola, illustrating his description 
by a drawing. He concludes this notice by stating his now con- 
firmed conviction of the separation of the sexes in the Heteropoda, 
of some of which he had obtained specimens which were indubit- 
ably females ; and he states, in reference to the male sexual organs — 
as the result of the examination of some hundreds of Heteropoda — 
that the vas deferens is never traced onwards to the external male 
organ, but that the penis is imperforate as in many of the Gastero- 
poda, is far in advance of the spermatic opening, and that these 
structures are held in communication by a ciliated groove, capable, 
more or less, of being converted into a canal. 
4 On the Zoological Characters of the living Clio caudata, 
as compared with those of Clio borealis given in Syste- 
tematic Works. By John Denis Macdonald, E.N., F.E.S., 
Surgeon of H.M.S. “Icarus.” Communicated by Professor 
Maclagan. 
The object of the author in this paper is to prove the importance 
