358 MEDUSAE OF THE WORLD. 



Living medusa of 0. tenuis frequently anchor themselves with much tenacity. There is, how- 

 ever, much variability in the degree of development of suckers upon some or all of the tentacles 

 in the various species of Olindiadae. This is well shown by comparing the figures given by 

 Maas, 1905, of the distal ends of the secondary tentacles of 0. malayensis , with those of 0. 

 tenuis given by Mayer, 1904. Bigelow, 1909, who found 12 specimens ot this medusa in 

 Mangareva Harbor, Paumotos, tropical Pacific, states that all of the tentacles bear ter- 

 minal, adhesive pads. He finds that the medusa closely resembles 0. tenuis, excepting tor 

 the fact that there is commonly but one lithocyst at the base of each primary tentacle. A 

 few lithocysts contain, however, 2 spherical concretions. Bigelow states that the medusa 

 is colorless, except for the gonads, which are reddish-brown to brick-red. 



He found an abnormal medusa with 2 manubria and 9 gonads, 4 of which were upon 

 the radial-canals and 5 on the centripetal vessels. 



Genus OLINDIOIDES Goto, 1903. 



Olindioides, Goto, 1903, Mark Anniversary Volume, article 1, pp. 3, 19.— Mayer, 1904, Memoirs Nat. Sci. Museum Brooklyn 

 Inst. Arts and Sci., vol. 1, p. 20. 



The type species, and only known form, is Olindioides formosa Goto, of the Bay of Tokyo, 

 Japan. 



GENERIC CHARACTERS. 



Olindiadas with 6 radial-canals, numerous blindly ending, centripetal canals, and two 

 sorts of tentacles. Of these, the exumbrella tentacles project at various levels from the sides 

 of the bell above the margin and bear adhesive pads. The velar or marginal appendages con- 

 sist of rudimentary tentacle-bulbs and elongated nematocyst-bearing tentacles. There are 2 

 inclosed lithocysts at the base of each exumbrella tentacle. Development unknown. 



Olindioides formosa Goto. 



Olindioides formosa, Goto, 1903, Mark Anniversary Volume, article 1, p. 3, plate 1, figs. 1-9; plate 2, figs. 14-16; plate 3, 

 figs. 17-20. 



Bell of adult medusa nearly hemispherical; that of young medusa somewhat higher than 

 a hemisphere. When adult the bell is about 75 mm. wide, being widest slightly above the 

 margin. Gelatinous substance thick and very consistent. There are two sorts of tentacles. 

 One kind arises from the velar margin and may be called velar tentacles; the tentacles ot 

 the other sort project outward from the exumbrella above the margin and may be called 

 exumbrella tentacles. 



In young medusae about 15 mm. wide there are about 70 exumbrella tentacles, but in a 

 specimen 75 mm. in diameter there were 264. The exumbrella tentacles may project outward 

 from the bell at any level from very near the apex to a short distance above the margin; their 

 entodermal cores traverse the jelly and are connected with the ring-canal. The majority ot 

 the exumbrella tentacles arise from a zone at a very short distance above the margin, but 

 others arise at various higher levels from the sides of the bell, and the roots of these latter 

 tentacles are correspondingly long and are accompanied by streaks ot thickened peronial 

 cells loaded with ivory-black pigment-granules. In young medusae very few of the exumbrella 

 tentacles arise from these higher levels, but as the medusa grows, more and more of them 

 migrate upward. The pigmented streaks marking the path of migration of the tentacles are 

 ectodermal peronia and are continuous with the nettle-ring of the bell-margin. 



The exumbrella tentacles are somewhat shorter than the bell-radius and are club-shaped, 

 expanding outwardly. There are numerous elongated nettling warts set transversely across 

 the tentacles, and the outer ends of the tentacles are slightly curled inward and provided with 

 a thick, elliptical pad of mucous gland-cells, which serves as a "sucker" to attach the animal. 

 This pad may be on the oral, aboral, or terminal part of the outer end of the tentacle. 



There are about 300 marginal bulbs, loaded with immature nematocysts, and about 10 

 to 15 highly-contractile, marginal tentacles. These are provided with many partial rings ot 

 nematocysts, the openings of the rings being on the inner (oral) side, and extending along this 

 open space there is a thick strand of striated muscle fibers. These velar, or marginal, tentacles 



