Antennal Amputations

Two crayfish were found with both antennal flagella missing. Eight were found with one flagellum absent and twenty-three with a part only of a flagellum absent. Six specimens were found with a small and apparently regenerated flagellum. The amputation of a part only of a flagellum must be a ease where the flagellum, in being broken off at a point distal to the autospasy point, has not been held long enough or strongly enough to cause autospasy. This suggests the existence of a minimum pulling stimulus necessary to cause autospasy.

The third segment of the peduncle and the flagellum of the antenna of one female were absent, while in another female these parts were regenerated. That regeneration of these parts occurs indicates that a point for autotomy or autospasy may exist in the junction of the second and third segments of the antennal peduncle.

A male was found with the second and third segments of the peduncle and the flagellum of one antenna missing, while a female had these parts regenerated. This indicates that a point for autotomy or autospasy may exist in the junction of the first and second segments of the antennal peduncle.

A tagged specimen, released without the flagellum of the left antenna, was found to have this almost completely regenerated after a period of 55 weeks, during which time it would have undergone two moults (Von Bonde and Marchand, 1935, p. 15).