130 



THE ANATOMY OF INVERTEBRATED ANIMALS. 



condition the gonophores of Athorybia may be cited (Fig. 

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

 Velella. 



In Athorybia, groups of gonophores, together with pyri- 

 form sacs, which resemble incompletely developed hydranths 

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

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

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

 upon separate branches of the gonoblastidium {androphores 



Fig. 27.— Athorybia rosacea.— A, gonoblastidium bearing three hydrocysts, a; gyno- 

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

 or gynophore, showing the included ovum, a, and the radical canals, b. C, D. 

 female gonophores enlarged ; a, aerminal vesicle ; b. vitellus; c, radial canals of 

 the imperfect nectocalyx ; d, canals oi the manubrial cavity. E y male gonophore. 



and gynophores). Each female gonophore contains only a 

 single ovum, which projects into the cavity of the imperfectly 



