10 Part [11.—Twenty-third Annual Report 
At 13 and 14 inches they were mostly four years of age, 
while some in which the lines of growth indicated five years 
measured 114, 143, and 18? inches, and one measuring 20 inches 
was shown to be four years old. 
The paper is illustrated by three plates showing the otoliths, 
scales, and bones. 
THE Lire-HIstory oF THE LOBSTER. 
In the present report will be found a paper, illustrated by four 
plates, in which Dr. H. C. Williamson gives the results of his 
observations on the life-history of the lobster. An account is 
furnished of the experiments on lobster-culture which were made 
at the hatchery, the “berried” or egg-bearing females being kept 
in a suitable tank, the larvee as they hatched being carried away in 
the overflow to receptacles where they were retained. Hatching 
was found to take place during the night, and the first young 
lobsters were observed on 11th July. 
The larval and early young stages which were reared at the 
Laboratory are described and figured in detail. Certain dimorphic 
forms of the zoéa were discovered among the larve, and they 
attracted attention, since, so far as known, such forms have 
not hitherto been recorded and described. Attention was directed 
to the behaviour of the lobsters during the time they were kept in 
confinement at the Laboratory, that is to say, three years in certain 
cases. Among them only one was known to have spawned its 
eggs. Casting occurred frequently, more frequently apparently 
than normally occurs with lobsters in the sea, and the increase in 
size immediately after moulting was found to be very small; 
reproduction, moreover, seemed to be inhibited. 
Various observations made on the condition of the ovary, the 
periods of spawning and hatching, the number of eggs carried by 
the female, the growth of the lobster, and on other points connected 
with its life-history and habits, are incorporated in the paper. 
Dr. Williamson also furnishes a further note on the life-history 
of the edible crab, treating specially of the hatching of the young. 
THE PARASITES OF FISHES. 
Dr. Thomas Scott, who is still prosecuting his researches on the 
parasites of fishes, contributes a paper on these organisms to the 
present report, in which several species not previously recorded 
from the Scottish seas are described, the descriptions being 
illustrated by a number of figures. This paper contains descriptions 
of seventeen species, twelve of which belong to the Crustacea and 
five to the Trematoda. 
One of the crustacean species described is found living in the 
nasal fossze of several kinds of fishes, as the cod, haddock, whiting, 
&e. Another was obtained in the mouth of a three-bearded rock- 
ling, and others on a sturgeon, a porbeagle shark, and other fishes. 
The Trematoda, which are leach-like in form, were obtained on 
the gills of the grey gurnard, the ballan wrasse, and the bass 
(Labrax lupus). 
