310 Mr. A. Hancock on a Burrowing Barnacle 
& 6) are of a yellow ochre colour, and the yolk is round and 
much smaller than the shell ; the yolk gradually assumes an ellip- 
tical form and soon fills the shell, it afterwards becomes a little 
flattened on one side (figs. 7 & 8), and by-and-by (figs. 9 & 10) 
three processes develope themselves from this part; these pro- 
cesses are the rudimentary arms: about this time a black spot, 
the eye, makes its appearance towards one end, and at the other 
the tail is seen to be forming ; afterwards these parts enlarge and 
gradually put on their perfect forms, while the egg mass assumes 
a full rose-colour. 
On examining an individual im which the eggs had been ex- 
posed, they were all found to be in a high state of development ; 
on applymg a powerful lens, I was delighted to find that nearly 
all the little creatures were alive, and most of them struggling 
for liberty. I soon had the satisfaction to observe several dis- 
engage themselves, and launch forth into the surrounding fluidd— 
free, natatory Crustaceans. In the course of a few hours nearly 
the whole were hatched, and the wine-glass in which they were, 
exhibited a most animated scene. On holding it up to the light 
they were quite visible to the unassisted eye as white points ; but 
with ihe aid of a magnifying-glass their motions could be accu- 
rately observed, and they were seen to resemble some of the En- 
tomostraca ; their large, smgle eye and general conformation show- 
ing their relationship to the genus Cyclops. They hung as it were 
suspended in the water, and every now and then dashed rapidly 
upwards with a fluttering, jerking motion. They commenced 
their ascent with great abruptness, and as abruptly became qui- 
escent again ; and once more hanging in the water were seen to 
descend slowly and gradually with their feet spread out above 
and their back’downwards. They seldom or never moved hori- 
zontally, their chief object apparently being to ascend either per- 
pendicularly or diagonally, and always in an inverted position. 
On placing a few of these minute beings (PI. IX. figs. 2, 3 & 4) 
under the microscope, each was found to be provided with a tail, 
the body being ovate, broad and depressed, having on the back 
an ovate shield tapering a little backwards and with a broad in- 
terrupted Jine (figs. 2 & 4a) of bright rose-colour towards the 
margins: it is to this line chiefly that the general mass of eggs 
has a rosy hue as they approach maturity. The eye is large and 
placed in the centre of the forehead ; it is of a very deep rose- 
colour,—almost black in some lights. The tail is more than half 
the length of the body, and passes from below the shield, and 
appears to be composed of two or three articulations: at first it 
is very stout, but rather suddenly narrowing, tapers gradually to 
a tolerably fine point and arches upwards ; on the under surface, 
at the point of contraction, there is a small curved spine. There 
