SOME MEDUSA OF JAPANESE WATEKS. 3 



The muscular system is well developed. The coroDal muscle 

 is a broad undivided band, of which the greater part is found 

 in the exumbrella, outside the bunches of secondary tentacles. 

 This is very remarkable, since we know of no parallel case in 

 any other species of Scyphomedusœ. A bundle of longitudinal 

 muscle is found at each corner of the central stomach cavity. 

 The muscle originates from the pyloric portion, and is found in 

 the wall of the stomach cavity. These perradial muscles are 

 broad, but weakly developed. The interradial muscles, however, 

 are well developed. They run from the aboral end of the peduncle 

 to the umbrella-margin. Each of these interradial muscles is 

 divided at the distal end into two short limbs for the adradial 

 bunches of tentacles. 



The connective tissue is well developed in the gelatinous 

 layer of the umbrella. There are found in it many long elastic 

 fibres running in different directions. 



The eight primary tentacles are transformed into small, cylind- 

 rical bodies. They are erect, hollow inside, and not adhesive. 

 They are black at base and along the axial median line. They 

 serve probably as a sensory organ standing in relation to light. 

 The secondary tentacles are short, capped ; each with a small 

 depression at the end of the distal cap. These tentacles are 

 grouped into eight adradial bunches, each of which consists of 

 about forty tentacles, growing in a lanceolate tract on the abaxial 

 side of oral arms. The tract is revolved, axially turned, and 

 resembles the similar tract oî Schizodiscus nagatensis.'-'' The ten- 

 tacles in the proximal part of the tentacular tract have very 

 large swollen stalks and degenerated urticating caps. The swelling 



''Kifehinouye — Some Scyphomedusœ of Japiiu. Jour. Coll. Sc. Tokyo. Vol. XVII, 7. 1902. 



