CHAP. VIIL DIASTYLID.E. 81 



Next to the extensive sections of the Stalk-eyed and 

 Sessile-eyed Crustacea, but more nearly allied to the 

 former than to the latter, comes the remarkable family 

 of the Diastylidse or Cumacea. The young, which Kroyer 

 took out of the 

 brood-pouch of 

 the female, and 

 which attained 

 one -fourth of Fig 52 16 

 the length of 



their mother, resembled the adult animals almost in all 

 parts. Whether, as in Mysis and Ligia, a transformation 

 occurs within the brood-pouch, which is constructed in 

 the same way as in Mysis, is not known. 17 The caudal 



16 Fig. 52. Male of a Bodotria, magn. 10 diam. Note the long 

 inferior antennae, which are closely applied to the body, and of which 

 the apex is visible beneath the caudal appendages. 



17 A trustworthy English Naturalist, Goodsir, described the brood- 

 pouch and eggs of Cama as early as 1843. Kroyer, 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 state- 

 ments 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 Diastylidae are full-grown animals or 

 larvae, 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 larvae (dee Van Beneden, ' Rech. sur la Faune littor. de Belgique,' 

 Crustacees, pp. 73, 74), induce me, on the basis of numerous investiga- 

 tions of my own, to declare in Van Beneden's words ; " Parmi toutes les 

 formes embryonnaires de podophthalmes ou d'e'driophthalmes que nous 

 avons observees sur nos cotes, nous n'en avons pas vu une seule qui eut 

 meme la moindreressemblance avec un Cuma quelconque." The only 

 thing that suits the larvae of Hippolyte, Palxmon and Alpheus, in the 

 family character of the Cumacea as given by Kroyer which occupies 

 three pages (Kroyer, ' Naturh. Tidsskrift, Ny Raekke,' Bd. ii. pp. 203 

 206) is : " Duo antennarum paria." And this, as is well known 



G 



