Note 1 — Chapter VIII · DEVELOPMENTAL HISTORY OF EDRIOPHTHALMA.

Leydig has compared this foliaceous appendage of the Water Slaters with the “green gland” or “shell-gland” of other crustacea, assuming that the green gland has no efferent duct and appealing to the fact that the two organs occur “in the same place.” This interpretation is by no means a happy one. In the first place we may easily ascertain in Leucifer, as was also found to be the case by Claus, that the “green gland” really opens at the end of the process described by Milne-Edwards as a “tubercule auditif” and by Spence Bate as an “olfactory denticle.” And, secondly, the position is about as different as it can well be. In the one case a paired gland, opening at the base of the posterior antennæ, and therefore on the lower surface of the second segment; in the other an unpaired structure rising in the median line of the back behind the seventh segment, (“behind the boundary line of the first thoracic segment,” Leydig).