330 NOTES, 
Note IV., CHAPTER I, p. 37. 
THE ECDYSES OF CRAYFISHES, 
There is a good deal of discrepancy between different observers as to 
the freqaency of the process of ecdysis in crayfishes, In the text I have 
followed M. Carbonnier, but M. Chantran (‘‘ Observations sur l’histoire 
naturelle des Ecrevisses :” Comptes Rendus, LXXI. 1870, and LXXIIL 
1871), who appears to have studied the question (on the “écrevisse 
& pieds rouges” apparently) very carefully, declares that the young 
crayfish moults no fewer than eight times in the course of the first twelve 
months. The first moult takes place ten days after it is hatched ; the 
second, third, fourth, and fifth, at intervals of from twenty to twenty-five 
days, so that the young animal moults five times in the course of the 
ninety to one hundred days of July, August, and September. From the 
latter month to the end of April in the following year, no ecdysis takes 
place. The sixth takes place in May, the seventh in June, and the eighth 
in July. In the second year of its age, the crayfish moults five times, that 
is to say, in August and in September, and in May, June, and July 
following. In the third year, the crayfish commonly moults only twice, 
namely in July and in September. At a greater age than this, the 
females moult only once a year, from August to September; while the 
males moult twice, first in June and July; afterwards in August and 
September. 
The details of the process of ecdysis are discussed by Braun, “ Ueber 
die histologischen Vorginge bei der Héutung von Astacus fluviatilis.” 
Wiirzburg Arbeiten, Bd. II. 
Note V., CHAPTER L., p. 39. 
REPRODUCTION IN CRAYFISHES, 
The males are said to approach the females in November, December, 
and January, in the case of the French crayfishes. In England they 
certainly begin as early as the beginning of October, if not earlier. 
According to M, Chantran (Comptes Rendus, 1870), and M. Gerbe 
(Comptes Rendus, 1858), the male seizes the female with his pincers, 
throws her on her back, and deposits the spermatic matter, firstly, on the 
external plates of the caudal fin ; secondly, cn the thoracic sterna around 
the external openings of the oviducts. During this operation, the 
appendages of the two first abdominal somites are carried backwards, 
