20 
Guide to Crustacea . 
Wall- the under surface of the thorax, between the last two pairs of legs, 
NosT 1-3 a cur i° us three-lobed structure with a slit-like opening in the 
middle, known as the “ sperm-receptacle.” 
As in most Crustacea, the eggs are carried, after spawning, by 
the parent Lobster, and, as in most of the higher Crustacea 
(Decapoda), they are attached to the swimmerets on the under 
Male. Female. 
Fig. 5. 
Male and Female Lobsters, showing the difference in the relative breadth 
of the abdomen in the two sexes. This figure also illustrates the dis- 
similarity of the large claws and the fact that the large “crushing-claw” 
may be on either the right or left side of the body. [Wall-Case No. 1.] 
surface of the abdomen. The female Lobster carrying spawn in 
this way is said by fishermen to be “ in berry.” A specimen in 
this condition is shown in spirit,, and a drawing, in natural colours, 
is hung in the upper part of the Case. The number of eggs carried 
by a single Lobster may vary from about 3,000 to nearly 100,000. 
Development. — Like most other Crustacea, the Lobster 
when hatched from the egg differs considerably in form from the 
