9 



than those of the male. This of itself is a good diagnostic point besides the 

 broad tail. The shell of the female is more convex than that of the male, 

 the male shell being nearly flat. On the underside of the apron or tail of the 

 female crab are seen a series of eight finger-like processes ; these finger-like 

 processes are double, are attached at their base, and are movable. In a 

 crab which is not in spawn, these projections are trimmed on each side with a 

 delicate hair-like substance, in general appearance not unlike the feather of a 

 quill pen. It is to these silken substances that the eggs are attached. In 

 the crab, curiously enough, no eggs are attached to the outer finger of each 

 pair of fingers, but only to the inner, by means of these hairs extending 

 on each side ; the outer fingers form a kind of nest for the protection of 

 the eggs, see Diagram No. 8. 



A crab carries eight bunches of eggs under her tail. These eggs are of a Eggs of cra&s. 

 beautiful red colour, even when unboiled, and perfectly globular ; they are not 

 unlike very minute herring roe. They are attached to the feathers by means *)f 

 a very delicate but strong'fibre, like very fine silk-worm gut, see Diagram No. 8. 

 When floating in the water they appear to be, as it were, threaded together like 

 beads in a necklace. From a calculation made by my secretary, Mr. Searle, it 

 appears that there are 180,180 eggs in one bunch of crab's eggs ; therefore there 

 must be no less than 1,441,440 eggs on the eight bunches of one crab. Mr. 

 Spence Bate, F.R.S., found in one she crab 2,000,000 ova. Previous to 

 spawning, the eggs are contained or carried immediately under the shell, 

 occupying at least one third of the whole space. This mass of eggs almost 

 fills the shell. (See coloured cast in my museum.) The eggs are carried inside 

 the shell for nine months before they are extruded ; in this condition they 

 are called the coral. The coral crab is especially esteemed at Aberdeen. 



On bending back the tail of the crab two round apertures on the hard shell 

 of the crab will be perceived. These* are covered with a drum-head-like 

 elastic substance, which is perforated in the centre. When a crab is about 

 to spawn these project. On passing a probe up these, it will be seen that 

 a direct communication exists between these holes and the mass of coral 

 under the shell. At the proper time of the year the eggs are extruded 

 from within the shell and become attached, by the silky thread already 

 mentioned, to the feather-like processes. How this attachment takes place 

 and how the eggs are transferred from inside the crab's body to the apron, I 

 am unable to say. It is, however, probably effected by means of the eight 

 ambulatory legs, which arrange the eggs as they are extruded from 

 the ovaries; the exact manner in which it is done I am unable to say, 

 but hope to find out by means of that valuable sea laboratory, the Brighton 

 Aquarium. 



A crab may be said to be marsupial ; she carries her eggs inside her body up 

 to a certain point; they are then deposited under this pouch. The reason of 

 this externa] gestation is obvious ; the embryo inside the egg requires water to 

 bring it to life. As, in the salmon, the young creature is not developed in the 

 egg for some time after its extrusion from the mother, so the mother-crab 

 carries about her eggs till the eyes of the embryo are developed in the egg, 

 and the young ones subsequently bursting the shell of the egg assume an 

 undeveloped existence as Zoea. When the eggs of the crab first appear under 

 the tail they are perfectly transparent. I have on one occasion examined the 

 eggs of a crab ; in each egg the eye of the embryo was distinctly visible; these 

 eggs would have shortly hatched out. According to Mr. Spence Bate the 

 horny shells of the eggs remain attached to the feathers of the tail when the 

 embryo escapes, and when the female sheds her shell she also sheds the husks 

 of the eggs. The London merchants brush out all the spawn from the fea- 

 thers under the tail. 



The crab when first escaping from the egg is not by any means a perfect Young of crabs, 

 shape. It is, indeed, very unlike a crab, and the young zoea until lately 

 were considered a distinct genus. " On leaving the egg," says Professor 

 " Rymer Jones,f the young crab presents a curious and grotesque figure; 

 " its body is hemispherical, and its back prolonged upwards into a horn-like 



* One witness told me that these were the teats of the crabs, and that the young ones sucked 

 from them, 

 t "General Outline of the Organization of the Animal Kingdom." 



