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Spiny Lobster, or Sea Cray-fish (Palinurus quadricornis). a. Left outward foot-jaw.

at Hamburg, Brighton, and the Crystal Palace, and the tanks were then crowded with transparent, leaf-like young, which, before then, were regarded as a distinct species, and called the “glass crab” (Phyllosoma). The common lobster (Homarus vulgaris) is an aquarium favourite, and although its colours are not so bright as those of the foregoing, the plum-tinted carapace is not without beauty; whilst its graceful motions in walking and climbing by means of its slender feet, and swimming either by the aid of the

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Embryo of common Lobster, magnified 20 diameters.

"swimmerets" arranged underneath the abdomen as so many fringed plates, or by one flap of the powerful expanded, fan-like divisions of the tail, give a good deal of animation to a tank. When several of these

YOUNG OF THE LOBSTER.

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crustacea are together the interest is much increased. The development of the young of the lobster, from the numerous eggs which the female usually carries under her body in dense masses, has recently obtained a good deal of attention. It is most interesting as indicating the nauplius stage, which characterises the early embryos of nearly all crustaceans alike, no matter what their adult differentiations may be. The young of the lobster pass through several stages

Fig. 190.

Larval or mysis stage of the common Lobster.

before they reach the adult condition. The first is visible before the egg is hatched. In this condition the carapace (b) is indicated by the presence of spots. of red pigment, the rudiments of the eye (c), antennæ

(d and e), of the great claws (g), and the bilobed tail (m), are plainly visible, as well as the most important of the internal organs, such as the heart (1), intestines (k), &c. On hatching, the second condition, called the mysis

Fig. 191.

Back view of fig. 190.

stage- because it then resembles the adult condition of the opossum shrimp, or Mysis-is next undergone. The young lobster is now about one-third of an inch in length, and, as will be seen in Fig. 190, possesses six pair of legs, one pair being subsequently modified into footjaws. In the third stage, when the larva has attained a length of about half an inch, it loses its mysis-like appearance, and begins to assume something like its adult features. In the mysis condition it swims on or near the surface of the water; and even in the next stage is more

or less of a free swimmer, these habits not being left off until after several succeeding stages of its developAt present it will be seen from Fig. 191 that

ment.

YOUNG OF LOBSTER.

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Even

rudimentary "swimmerets" have appeared on the second to the fifth segments of the abdomen, whilst the large claws are in process of formation. after the young have reached what is called the adult stage, they are so unlike fully developed lobsters that they might be regarded as a different genus. Their movements are now very much like those of shrimps, and they frequent the surface of the water much more than the bottom. All the above changes are believed to take place in a single season.

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Like all the crustaceans, thick-tested species particularly, the lobster increases in size by moulting or casting off its old coat, which is thrown off in one. piece, and looks so perfect that it might be taken for the animal itself. Not unfrequently it casts an odd

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