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THE AMERICAN NATURALIST [Vol. XL 



The activities of the female connected with egg-laying may be 

 divided, for convenience of description, into four periods. First, 

 the preparatory cleansing of the under side of the abdomen and 

 thorax. This lasts four or five days and has been described in 

 the previous paper. Second, the period of secretion of mucus, 

 or "glairing" as we may call it, to be described below. Third, 

 the period of actual extrusion of eggs, previously inferred but 

 described below as actually seen. Fourth, the rhythmic alter- 

 nation of position of the body, or "turning," lasting several hours 

 and described in the previous paper. 



All these processes precede the long care of the eggs as they 

 hang fastened to the abdominal legs for from five to eight weeks 

 till they hatch, after which there is a brief period of association 

 of female and young before the latter scatter and become inde- 

 pendent. 



The least well observed process is that of secreting glaire from 

 the glands of the abdominal appendages and sterna. It always 

 follows the long and very laborious cleansing of those surfaces 

 and immediately precedes the extrusion of eggs so that as soon 

 as the glaire is ready and the female properly posed, the eggs pass 

 out into the glaire, one period passing insensibly into the other. 

 At the time of secretion the female is still easily alarmed and 

 moreover the glaire is at first seen with difficulty as it is like water 

 in refraction, so that in most cases the "glairing" period escaped 

 observation. But as far as was made out the secretion of the 

 glaire took less than half an hour, though Chantran speaks of 

 Astacus as secreting mucus for several hours. Possibly some 

 of this time was taken up with "cleansing," which has not yet 

 been noticed in Astacus. But if there is an actual time difference 

 between Cambarus and Astacus it may be due to differences in 

 temperature since Astacus lays in winter and this Cambarus in 

 spring. 



The details of the activities of a crayfish observed during the 

 "glairing" process were in one case as follows. At first the 

 animal kept the same unusual attitude assumed in cleansing 

 itself, that is, it stood high up on its legs with the thorax and 

 abdomen raised far above the bottom. The abdomen was bent 

 forward loosely and its caudal fan reached nearly as far as the 



