Note 7 — Chapter VIII · DEVELOPMENTAL HISTORY OF EDRIOPHTHALMA.

A trustworthy English Naturalist, Goodsir, described the brood-pouch and eggs of Cuma as early as 1843. Kröyer, whose painstaking care and conscientiousness is recognised with wonder by every one who has met him on a common field of work, confirmed Goodsir’s statements in 1846, and, as above mentioned, took out of the brood-pouch embryos advanced in development and resembling their parents. By this the question whether the Diastylidæ are full-grown animals or larvæ, is completely and for ever set at rest, and only the famous names of Agassiz, Dana and Milne-Edwards, who would recently reduce them again to larvæ (see Van Beneden, ‘Rech. sur la Fauna littor. de Belgique’ Crustacées, pp. 73, 74), induce me, on the basis of numerous investigations of my own, to declare in Van Beneden’s words; “Parmi toutes les formes embryonnaires de podophthalmes ou d’édriophthalmes que nous avons observées sur nos côtes, nous n’en avons pas vu une seule qui eût même la moindre resemblance avec un Cuma quelconque.” The only thing that suits the larvæ of Hippolyte, Palæmon and Alpheus, in the family character of the Cumacea as given by Kröyer which occupies three pages (Kröyer, ‘Naturh. Tidsskrift, Ny Raekke,’ Bd. ii. pp. 203–206) is: “Duo antennarum paria.” And this, as is well known, applies to nearly all Crustacea. How well warranted are we therefore in identifying the latter with the former. However, it is sufficient for any one to glance at the larva of Palæmon (Fig. 27) and the Cumacean (Fig. 52) in order to be convinced of their extraordinary similarity!