480 JOURNAL OF SCIENCE. 
embryo has an elongated pyriform shape, the broad end being 
anterior, and the narrow or posterior end produced into a long 
canal. On what may be described as the “hairy” in contra- 
distinction to the smooth side of the egg-shell, there is on each side 
of the middle line at the anterior end a longitudinal slit in the 
wall of the cavity, which serves to allow of currents to. and from 
the latter, for respiratory purposes. The anterior ends of these slits 
are united by a weak place in the wall of the egg-shell; very slight 
pressure from within causes rupture along this line and produces 
a valve, the lateral boundaries of which are formed by the respira- 
tory slits, its anterior boundary by the line ofrupture. This valve 
readily opens outwards by pressure on its inner face, and serves 
for the exit ot the foetus; pressure upon its outer face only forces 
it against the opposite wall of the cavity. 
The advanced embryo lies in the cavity in such a position that 
its head lies at about the line of the base or hinge of the valve, and 
therefore some distance trom the anterior end of the cavity, its tail 
lies in the narrow posterior prolongation of the cavity, which fits it 
accurately ; its right side lies almost invariably against the smooth, 
its left against the hairy side of the egg-shell. 
Unfortunately the embryos in all the four dozen eggs examined 
were in a tolerably advanced stage of development, so that there 
will be little chance of getting younger stages until next autumn. 
The youngest obtained are about 4 inches long; they have large 
yolk-sacs (1.75 inch inlength), and very long external gills project- 
ing from the opercular aperture; the snout has acquired the 
characteristic form, but the tail shows as yet no trace of hetero- 
cercality, nor the skin of the silvery character it has in the adult, 
being in the fresh state translucent and highly vascular. The 
yolk-sac is remarkable; it is longitudinally elongated, and pro- 
duced into numerous blunt paired projections, which are tolerably 
constant in position; one pair of these always lies to the anterior 
end of the dorsal surface of the yolk-sac, and between them the 
snout of the embryo is invariably situated. The umbilical or 
somatic stalk is practically obsolete, the foetus being sessile upon 
the yolk-sac. 
As in Elasmobranchs the yolk-sac is gradually drawn into the 
ccelome, and so consists in advanced stages of an internal and an 
external portion, the former continually increasing at the expense 
of the latter. As the external portion diminishes in size, it loses its 
blood-vessels, and its projections gradually disappear. In the 
latest stage obtained, the external portion is not more than 0.5 
inch long, the internal portion being fully 1.25 inch in length, and 
causing a great distension of the abdominal walls. In this stage 
also, the external gills are absorbed, and the adult characters of the. 
integument attained. 
In the discussion which followed, Mr. R. Gillies suggested the 
probability of the eggs being laid among the kelp, and becoming 
afterwards covered with sand through the heavy seas so prevalent 
on these coasts. 
The President and Secretary gave an account of the arrange- 
ments made by the Council for the present session of the Institute, 
They stated that it had been decided to hold the meetings regularly 
on the second Tuesday in each month, from May to November ; 
that the reading of original papers was to be confined to alternate 
