130 



THE ANATOMY OF INVERTEBRATED ANIMALS. 



condition the gonophores of Athoryhia maj be cited (Fig. 

 27) ; of the latter, the gonophores of Physalia^ Porpita^ and 

 Velella. 



In Athoryhia, groups of gonophores, tog-ether with pyri- 

 form sacs, which resemble incompletely developed hydranths 

 {hydrocysts — Fig. 27, A, «), are borne upon a common stem, 

 and constitute a gonohlastidium (Fig. 27, A). The groups 

 of male and female gonophores (Fig. 27, A^ h, c) are borne 

 upon separate branches of the gonoblastidium (androphores 



Fig. 27. — Athoryhia romcea.—A, gonoblastidium bearing tbree hydrocyets, a; gjao- 

 phore, b ; and two androphores, c. B, female gonophores on their common stem 

 or gynophore, showinir the included ovum. a. and the radical canals, b. O, Z>, 

 female gonophores enlarged ; a. cerminal ve-^icle ; b, vitellus; r, radial canals of 

 the imperfect uectocalyx ; d, canals ol the mauubrial cavity. E, male gonophore. 



and gynophores). Each female gonophore contains only a 

 single ovum, which projects into the cavity of the imperfectly 



