68 Part I1].—Twenty-third Annual Report 
For the journey to Fraserburgh the larve were packed at 3.15 p.m., 
and were set free at 7.15 p.m., at which time they were all quite lively. 
The vitality of the young lobster under certain conditions is remark- 
able. Herrick kept them alive in small flat dishes, without change of the 
water, from one to four days at a time, or until they moulted to the 
second stage. A case in point occurred at the Laboratory. After one of 
the journeys to Fraserburgh a few larve had been left in the dregs of 
water in one of the carboys. They were discovered 10 days later, and 
were then alive and active. Two small crabs (Carcinus menas) were 
kept for a week in a little glass cell without change of water, and 
apparently suffered no ill-effects. 
There was a considerable mortality among the larval lobsters when in 
the hatchery. As has been so often noted, a proportion of the deaths 
occurred during moulting. The dead lobsters were sometimes partly 
eaten. No case was seen of one zoéa attacking and killing another, such 
as Herrick witnessed. A case of cannibalism was noticed in the 
megalops stage. One megalops was seen eating the tail of another which 
was still alive. The telson and part of the abdomen had been eaten off 
when discovered. A cause of considerable mortality is probably starva- 
tion. It is difficult to supply suitable and sufficient food. 
All the lobster eggs were hatched out by September 10, 1902. 
THE REARING OF LOBSTERS. 
There are two well-marked stages in the life of the lobster fry: these 
are (1) the first swimming stage, when just hatched (fig. 66, pl. iv.), 
and (2) the stage when it for the first time takes on the form, and, toa 
certain extent, also the habits, of the adult (fig. 72, pl. iv.). The former 
is the first zoéa stage, the latter is the megalops stage. Previous to the 
first zoéa stage there is the protozoéa, a stage of short duration. The 
lobster has been described as issuing from the egg as a protozoéa. This 
condition was not observed by the writer. It moults very soon after, 
and becomes a zoéa of the first stage. R. @. Couch was the first to 
figure and describe the protozoéa. He wrote as follows :—‘“‘Several of 
the ripest bunches of ova were taken off, and by gentle agitation many 
of the young escaped and swam about very freely, like those of the 
common crab, and some were artificially extracted to leave no doubt to 
rest on their parentage. Their bodies are large, stout, and of a deep blue 
colour, while the other parts are semi-transparent and dotted with red. 
The eyes are large, sessile, situated on a festoon at the lower and anterior 
margin of the dorsal shield, and marked at the circumference with radia- 
ting lines. The interior margin of the shield is waved, and irregularly 
prominent ; the posterior and lateral surfaces are more remarkably so, 
and are rough, with minute papillary eminences ; and the lower margin is 
marked with seven minute plaited folds, beneath the five central ones 
are situated five claws on either side. They are jointed as in the adult, 
and the anterior pair are shorter and stouter than the others, and ter- 
minate in a pair of nippers. The tail is longer than the diameter of the 
body, is extended and composed of five annulations. The termination is 
forked, but the fork is composed of two flat fan-like expansions separated 
by a fissure which extends nearly as high up as their articulation.” 
Saville Kent and Fullarton also give drawings and descriptions of this 
stage. 
The megalops stage is one in which the lobster in its habits resembles 
more a prawn (Palemon), as Saville Kent pointed out. The interval 
which exists between the first zoéa and the megalops has been filled in 
by a varying number of stages. Herrick, for the American lobster, 
