Medusae of the world . RLD. The velum is simple, annular, and provided with powerful circular muscles. The mouthis a simple annular opening at the thick lenticular center of the subumbrella. 28 simple, unilocular saccules project downward into the bell-cavity at the stomach-margin, one in each antimere. These bag-like protrusions thus alternate with the radii of thetentacles and contain the genital organs, the specimen being a male. The marginal ring-canal,or festoon-canal, is very wide. It extends down the sides of the peronial strand on eitherside of the insertion of each tentacle and along
Medusae of the world . RLD. The velum is simple, annular, and provided with powerful circular muscles. The mouthis a simple annular opening at the thick lenticular center of the subumbrella. 28 simple, unilocular saccules project downward into the bell-cavity at the stomach-margin, one in each antimere. These bag-like protrusions thus alternate with the radii of thetentacles and contain the genital organs, the specimen being a male. The marginal ring-canal,or festoon-canal, is very wide. It extends down the sides of the peronial strand on eitherside of the insertion of each tentacle and along the margin of each lappet. It is thus brokenup into 28 loops, one in each antimere. The gelatinous substance of the bell is hyaline. The tentacles, gonads, stomach, andfestoon-canal are milky—slightly brown in formalin. The medusa is probably immature, for half of its tentacles are of small size and belongapparently to a set which is in process of development. The specimen is perfect and is wellpreserved in Fig. 298A.—Pegantha clara. A, side view. B, oral view of part of bell-margin showing velum (V), otoporpie (op), andinsertions of long set of tentacles (ti). C, oral view of part of bell-margin, showing genital saccules of subum-brella (go), otoporpae (op), peronial strands, (p), marginal festoon-canal (ric), and tentacles (t). It is distinguished from P. cyanostylis by having only 2 to 5 sense-clubs upon each lappet,whereas in P. cyanostylis there are 25 or 30. It is distinguished from P. punctata by iislong, slender tentacles. It is due to the generous permission of Prof. Robert P. Bigelow that I am permitted notonly to study the single specimen of this rare medusa, but also to copy the excellent figureswhich he made of it soon after its capture by the U. S. Fish Commission steamer Fish Hawkon the surface, near the borders of the Gulf Stream, off Woods Hole, Massachusetts, in Sep-tember, 1899, Station No. 7068. Pegantha smaragdina H. B. Bigelow. Pegantha smar
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectcnidari, bookyear1910
