480 



MEDUSJE OF THE WORLD. 



Cunina prolifera Gegenbaur. 



Cunina prolifera, Gegenbaur, 1854, Generationswechsel bei Medusen und Polypen, p. 56, taf. 2, fign. 24-31, Wiirzburg; 1856, 



Zeit. fur wissen. Zool., Bd. 8, p. 262. — Haeckel, 1879, Syst. der Medusen, pp. 313, 320. 

 Eurystoma rubiginosutn, Kollikfr, 1853, Zeit. fur wissen. Zool., Bd. 4, p. 322. 

 JEgineia rosea, Gegenbaur, i8c6, Zeit. fur wissen. Zool., Bd. 8, p. 261, taf. 10, fign. 6, 7. 

 Cunina rhododaetyla +C. rubiginosa, Haeckel, 1864, Jena. Zeitschr. fiir Naturwissen., Bd. I, p. 335; Bd. 2, p. 263, taf. 9; 



1865, Familie der Riisselquallen, p. 125, taf. 6, fign. 78-85; 1879, Syst. der Medusen, pp. 313, 321. 

 Cunina rhododactyla, Metschnikoff, E., 1874, Zeit. fiir wissen. Zool., Bd. 24, p. 29, taf. 5 (development); 1886, Arbeit. Zool. 



Inst. Wien, Bd. 6, p. 252. — Maas, 1904, Result. Camp. Sci. Prince de Monaco, fasc. 28, p. 32, plate 2, fig. 15. — Stschel- 



kanowzeff, 1906, Mitth. Zool. Sta. Neapel, Bd. 17, p. 482. 

 Mginela gemmifera, Keferstein und Ehlers, 1861, Zoolog. Beitrage aus Neapel und Messina, p. 93, taf. 14, fign. 10, n. 



The bell becomes 16.5 mm. wide. The gelatinous substance above the stomach is very 

 thick and the aboral part of the bell is dome-like and evenly rounded. The bell-collar, on 

 the other hand, is thin, flexible, and contractile. When expanded the lappets are about 

 two-thirds as long as the bell-radius and their free, lower margins are evenly rounded. There 

 are 4 to 8 sensory-clubs on each lappet. Each club arises by a very narrow stalk from a bristle- 

 bearing pad on the bell-margin. The club contains at its distal end a single, red-colored, 

 crystalline concretion of entodermal origin. A thick, linear otoporpa arises from the basal 

 pad of each sensory-club and extends upward for a short distance over the exumbrella side 

 of the lappet. The velum is well developed and provided with powerful, circular muscles. 



The tentacles, and consequently the lappets, are remarkably variable in number, ranging 

 from 7 to 16. There are usually 9 or more tentacles and lappets, but the actual number is so 

 inconstant that there is no well-defined mean. Thus, among 36 medusae studied by me at 

 Naples during the winter of I 907-1908, 1 had 7 tentacles, none had 8, 7 had 9, 5 had 10, 6 had 



Fig. 320.— Cunina prolifera. Drawn by the author, from sections, at Naples Zoological Station. Ectodermal nuclei are 

 shown as black dots while the entodermal nuclei are represented as circles. A, radial section through medusa in 

 radius of sense-club; m, medusae of first sexual generation floating in stomach-cavity of parent; o, mouth of young 

 medusa; or, sensory-club of the parent medusa; otp, otoporpa; re, marginal ring-canal; v, velum. B, median 

 section of one of the medusae found in stomach-cavity of parent. This medusa is developing an aboral medusa- 

 bud, o, mouth; st, stomach; t, tentacle. 



11, 3 had 12, 5 had 13, 5 had 14, 1 had 15, 3 had 16. The tentacles taper gradually to their 

 tips, are quite flexible, but not very contractile. They range in length from two-thirds to as 

 long as the bell-radius. Their number does not increase with age in the free-swimming 

 medusa, for large specimens often have a small number and young medusae a larger number of 

 tentacles. The rusty-red or port-wine color of the entoderm of the tentacles is very character- 

 istic of this species. The tentacle-roots penetrate the gelatinous substance of the bell, so that 

 there is a narrow, slit-like cleft in the side of the bell at the place of insertion of each tentacle. 

 The stomach is flat and lenticular and the mouth is a round opening with puckered lips 

 at the extremity of a very short throat-tube, which never projects to the level of the velum. The 

 marginal stomach-pouches, in the tentacular radii, are mere notches, rounded outwardly under 

 the roots of the tentacles. The marginal, peronial, ring-canal system is well developed (see 

 />. c. in text-figure 319 C). The annular gonad is in the ectoderm around the margin of 

 the subumbrella floor of the stomach. 



