NOTE VI., CHAPTER I., p. 42. ATTACHMENT OF THE YOUNG CRAYFISH TO THE MOTHER.

NOTE VI., CHAPTER I., p. 42. ATTACHMENT OF THE YOUNG CRAYFISH TO THE MOTHER.

I observe that I had overlooked a passage in the Report on the award of the Prix Montyon for 1872, Comptes Rendus, LXXV. p. 1341, in which M. Chantran is stated to have ascertained that the young crayfishes fix themselves “en saisissant avec un de leurs pinces le filament qui suspend l’œuf à une fausse patte de la mère.”

In the paper already cited from the Comptes Rendus for 1870, M. Chantran states that the young remain attached to the mother during ten days after hatching, that is to say, up to the first moult. Detached before this period, they die; but after the first moult, they sometimes leave the {352} mother and return to her again, up to twenty-eight days, when they become independent.

In a note appended to M. Chantran’s paper, M. Robin states, that “the young are suspended to the abdomen of the mother by the intermediation of a chitinous hyaline filament, which extends from a point of the internal surface of the shell of the egg as far as the four most internal filaments of each of the lobes of the median membranous plate of the caudal appendage. The filaments exist when the embryos have not yet attained three-fourths of their development.” Is this a larval coat? Rathke does not mention it and I have seen nothing of it in those recently hatched young which I have had the opportunity of examining.