98 Part IT. —Twenty-third Annual Report 
THE Errect oF THE ExposurRE oF THE LossTERS TO StTROoWG LicHT. 
A number of lobsters have been kept out of doors, in tanks which were 
without covering. In two of the tanks the bodies of the lobsters were 
hidden by the wooden shelf which formed the common roof to their pens ; 
one large concrete tank afforded them no cover whatever. In the former 
the antennz of the inmates were exposed to direct daylight, and they 
very often had pieces of seaweed and smaller ectozoa growing on them 
during the summer. ‘Two females were kept in the concrete tank from 
the autumn of 1902 till September 1903. At the latter date they were 
completely covered and hidden by a prolific growth of seaweeds, 
Laminaria sp., young mussels, &c., which completely occupied the 
dorsum of each shell-fish (vide fig. 73, pl. iv.). The covering appeared 
to be of some inconvenience to the lobster in walking. While the 
growth of the seaweeds was, no doubt, directly due to the exposure to 
daylight, it is probable that it was permitted by the host asa shelter in 
the exposed tank. The shells of the pair were clean when they were 
put into the tank. Herrick records examining a number of lobsters 
which were adorned with more or less extensive collections of seaweeds 
and other ectozoa. On none of the lobsters captured in the sea and sent 
to the Laboratory was there any coat of seaweed. The ectozoa usually 
consisted of tubes of Serpula sp., Balanus sp. One of the two cast its 
shell on 19th October 1903, and a drawing has been made from the cast 
shell (fig. 73, pl. iv.). It lived until May 1904. The other lobster did 
not cast, but remained covered with seaweed during the winter ; it also 
was found dead in May 1904. 
Bopy Fuurp. 
The body fluid of the lobster is richly albuminous. It is colourless 
when fresh, but soon congeals on exposure to air to a clear jelly with a 
slightly biown tint. Alcohol (94 per cent.) causes the blovd to 
coagulate at once, 
DIssEcTION.— EXAMINATION OF THE UVARY. 
Almost without exception, the ovaries of the lobsters examined, 
measuring 9 inches and over in total length, were found to contain eggs as 
large, or nearly as large, as ripe eggs. When the eggs are large, yolked, and 
approaching ripeness the ovary is black in colour ; the eggs themselves 
are black, although the yolk is really a very dark-green colour. The 
ovary turns red in alcohol. 
The lobsters were broadly distinguished as (a) berried, (0) lobsters 
which had lately hatched their eggs, (c) soft. 
(a) Berried Hens. 
(1) December 21, 1904.—A lobster (from Dunbar) measured 
114 inches in length. The shell wasclean. The external eggs were black, 
showing no pink-coloured part, simply a light-green formative part. The 
eggs were evidently early. The ovary was white, but contained green 
eggs measuring ‘4 and ‘5 mm. ‘The smaller green eggs contained simply a 
core of green yolk, surrounded by a periphery of white yolk (by trans- 
mitted light). The oviducts were filled with a greenish fluid. 
(2) February 19, 1905.—In a lobster (from Dunbar) the external eggs 
were well advanced ; the pink area was about one-fifth of the whole egg. 
The ovary was large and black in colour. 
