172 THE VOYAGE OF H.M.S. CHALLENGER. 



(sh). The contractile and very mobile proboscis (sr) terminates in a suctorial mouth, 

 the margin of which sometimes is regularly octolobate (fig. 3, ss). 



Tentacles (figs. 1, 2, 3, t, 8). — The single tentacle which arises from the pedicle of each 

 siphon in the most dorsal part of the bract-cavity is of the form usual in Calyconectse. 

 It is very long and contractile, and beset with very numerous equidistant tentilla. 

 Each of the latter (fig. 8) bears on its pedicle an elongated reniform cnidosac (tk), and this 

 contains on each side of the cnidoband (km) a group of six to eight large ensiform 

 cnidocysts (kl). The pedicle (tt) as well as the terminal filament (tf) is inflated and 

 vesicular at the distal end. 



Special Nectophores (figs. 2, nn, 6). — The special nectophore of each cormidium, 

 which is placed in the ventral part of the bract-cavity, offers in Desmophyes a most 

 interesting medusiform structure, similar to that of Lilyopsis. The umbrella is bilaterally 

 symmetrical, since its jelly-mass is more developed in the dorsal than in the ventral 

 part ; it arises by a conical pedicle, which fits into the apex of the bract-cavity. The 

 pedicular canal, which arises from the common stem, does not enter into the apex of 

 that pedicle, but into the middle of its dorsal edge (fig. 6, cp). 



The subumbrella of the special nectophore (to) is hemispherical, occupies its basal 

 half and opens by a wide mouth, surrounded by a broad velum (v). The four radial 

 canals (cr), which arise from its apex, are united at its margin by a circular canal (cc). 

 The margin of the umbrella, beyond the latter, is beset with eight red pigment spots or 

 ocelli (uy), four of these lie perradially (at the distal end of the radial canals), four others 

 in the middle between them. They are relatively larger than in the main nectophores. 

 Besides, the margin of the umbrella is beset with a corona of sixteen short tentacles (t) ; 

 eight placed beyond the ocelli, and eight others alternating with these, between the former. 



Gonophores (figs. 2, f, 4, 5). — Desmopjhyes is monoecious and diclinic, both sexes 

 alternating so regularly that each cormidium has gonophores of one sex only, and two 

 neighbouring gonophores always being of different sexes, forming together a pair. 

 Each cormidium bears only one fully-developed gonophore ; but at its base are placed 

 the buds of several reserve gonophores. They lie between the dorsal siphon and the 

 ventral special nectophore. 



Androphores (fig. 4). — The male gonophores exhibit, fully developed, a very large, 

 spindle-shaped manubrium (Am), with a cylindrical central spadix (hx); it is widely pro- 

 minent from the cavity of the small retracted umbrella (u) ; the latter envelopes only the base 

 of the former, but exhibits four distinct radial canals (cr) and a uniting circular canal (cc). 



Gynop>hores (figs. 2,f, 5). — The female gonophores have a campanulate umbrella (f) 

 larger than that of the males, also with four well-developed radial canals (cr) and a 

 connecting circular (cc). The cavity of the subumbrella in ripe females is filled by a 

 large pyriforrn or subglobular manubrium, which contains usually four large ovules of 

 equal size, disposed in form of a cross (o). 



