416 Proceedings of Boy al Society of Edinburgh. [july 2, 
phausia; but we have been better able to trace the life-history of 
the latter genus on account of certain peculiarities which are early 
developed. 
Early in the month of April of the present year, Dr John 
Murray called attention to some eggs and hlauplii which he had just 
taken by the surface-net in the Firth of Clyde, and which he 
suspected might be those of the Euphausiidse {Nyctiphanes and 
Boreophausia) captured by the tow-nets at somewhat greater depths 
in the same localities. 
From observations made on the “Medusa,” from April 14 to 16- 
we are enabled to give the following particulars regarding the eggs 
and Nauplius: — 
I. The Eggs. 
Two kinds of eggs were met with, which from their relative 
dimensions may be conveniently designated the larger and smaller. 
1. The smaller Eggs measured about 0*5 mm. in diameter, and 
consisted of a perfectly transparent, and, to all appearance, homo- 
geneous external envelope, which showed a double contour under a 
Zeiss’ objective D. Within this was a clear space surrounding the 
blastospiiere, which measured 0*3 mm. in diameter. In most cases 
segmentation had proceeded so far that the whole outer surface was 
covered with flattened ectodermal cells, in which the nucleus was 
distinctly visible. 
In one instance the rudiments of one pair of larval appendages 
were observed, as small rounded prominences situated opposite to 
each other near one aspect of the sphere. We could, however, find no 
means of deciding whether these represented the anterior or posterior 
of the appendages of the Hauplius. 
In some other examples the three pairs of typical Nauplius- 
appendages were clearly present, and then the embryo had the follow- 
ing appearance. Its body had the form of a short blunt wedge, 
with the angles rounded off, the narrower edge corresponding with 
the future ventral aspect. On either side, and completely covering 
it, were situated three short cylindrical bodies, with rounded ends, 
placed side by side. They were precisely similar in appearance and 
subequal in size, so that it was impossible to decide which was the 
anterior extremity of the future Crustacean. 
