“At this time they are quite transparent; and when such a crayfish [a female with young] is brought to table, it looks quite disgusting to those who do not know {42} what the young are; but if we examine it more closely, especially with a magnifying-glass, we see with pleasure that the little crayfish are already perfect, and resemble the large one in all respects. When the mother of these little crayfish, after they have begun to be active, is quiet for a while, they leave her and creep about, a short way off. But, if they spy the least sign of danger, or there is any unusual movement in the water, it seems as if the mother recalled them by a signal; for they all at once swiftly return under her tail, and gather into a cluster, and the mother hies to a place of safety with them, as quickly as she can. A few days later, however, they gradually forsake her.”[4] Fishermen declare that “Hen Lobsters” protect their young in a similar manner.[5] Jonston,[6] who wrote in the middle of the seventeenth century, says that the little crayfish are often to be seen adhering to the tail of the mother. Roesel’s observations imply the same thing; but he does not describe the exact mode of adherence, and I can find no observations on the subject in the works of later writers. [4] “Der Monatlich-herausgegeben Insecten Belustigung.” Dritter Theil, p. 336. 1755. [5] Bell’s “British Crustacea,” p. 249. [6] “Joannis Jonstoni Historiæ naturalis de Piscibus et Cetis Libri quinque. Tomus IV. ‘De Cammaro seu Astaco fluviatili.’” It has been seen that the eggs are attached to the swimmerets by a viscid substance, which is, as it were, smeared over them and the hairs with which they are {43} fringed, and is continued by longer or shorter thread-like pedicles into the coat of the same material which invests each egg. It very soon hardens, and then becomes very firm and elastic. When the young crayfish is ready to be hatched, the egg case splits into two moieties, which remain attached, like a pair of watch glasses, to the free end of the pedicle of the egg (fig. 8, A; _ec_). The young animal, though very similar to the parent, does not quite “resemble it in all respects,” as Roesel says. For not only are the first and the last pairs of abdominal limbs wanting, while the telson is very different from that of the adult; but the ends of the great chelæ are sharply pointed and bent down into abruptly incurved hooks, which overlap when the chelæ are shut (fig. 8, B). Hence, when the chelæ have closed upon anything soft enough to allow of the imbedding of these hooks, it is very difficult, if not impossible, to open them again.