220 



MEDUSAE OF THE WORLD. 



GENERIC CHARACTERS. 



Thaumantiadae with 4 radial-canals and a ring-canal, all of which give off blindly ending, 

 dendritic side branches. Bell-margin cleft into lappets. Stomach mounted upon a peduncle, 

 and with 4 lips. Gonads sac-like, complexly folded, and developed upon the radial-canals 

 adjacent to sides of stomach. 



This genus resembles Polvorchis, but ring-canal gives off blindly ending, centripetal 

 branches, and margin is cleft into lappets. 



Spirocodon saltatrix Haeckel. 



Medusa saltatrix, TILESIUS, 1818, Mem. Acad. St. Petersbourg, tome 6, p. 554, taf. 18. 

 Polyorcliis saltairix= Spirocodon saltatrix, HAECKEL, 1880, Syst. der Medusen, p. 636. 



Spirocodon sa/tatrix, GOETTE, 1886, Sitzungsber. kgl. Preussisch. Akad. Wissenschaft. zu Berlin, Jahrg., 1886, p. 832. 

 Goneomeandrus chryiostephanus, KIRKPATRICK, 1903, Annals Mag. Nat. Hist., ser 7, vol. 12, p. 616, plate 33, figs. 1-4 (this is 

 Spirocodon saltatrix Haeckel; see Kirkpatrick, 1904, Annals and Mag. Nat. Hist., ser. 7, vol. 13, p. 80). 



Bell with octagonal sides and dome-like, rounded top, angles of side-walls radial and in- 

 terradial in position, 30 to 60 mm. wide, 50 to 80 mm. high. 8 adradial, semicircular, marginal 

 lappets. The clefts between the lappets pass obliquely upward and outward from below and 

 extend much higher on the exumbrella than on the subumbrella side, so that only the outer 

 third of each lappet is free. The lappets alternate in position with the angles of the sides of 

 the bell. Velum quite broad, its inner edge circular. 



112. 



"3- 



FIG. 112. Spirocodon sallatrix, after Kirkpatrick, in Annals and Mag. Nat. Hist. 



FIG. 113. Cannota dodccantha, after Agassiz and Mayer, in Bull. Museum Comp. Zool. at Harvard College. 



There are about 40 to 80 tentacles on each of the 8 lappets, 326 to 640 in all. These ten- 

 tacles arise in a single row from the margin, and are about one-third as long as bell-diameter. 

 Their bases are hollow and narrower at margin than at some distance out. There is an 

 orange-brown ocellus above the base of each tentacle and there are no other marginal sense- 

 organs. There are 4 radial-canals and a ring-canal which extends around the margins of the 

 lappets. All of these canals give off numerous blindly ending, dendritic side branches, which 

 do not anastomose. 4 main centripetal vessels arise from the interradial angles of the mar- 

 ginal ring-canal and smaller ones arise from the ring-canal in adradial and other positions. 



The stomach is set upon a short, gelatinous peduncle which is one-thud as wide as the bell 

 itself and as long as wide; it is cruciform in cross-section, 4-sided, and about half as long as 



