18 NEW INVERTED RATA FROM 



ji brilliant blue border. The portion near the float is yel- 

 low. The outer edge of the umbrella is entire. 



Seen from below the oval float was observed to bear three 

 kinds of api)endages, which may be known as the polypites, 

 the sexual bodies and the tentacles. The polypite, or cen- 

 tral polyp, is a highly contractile, flexible body, capable of 

 considerable motion, enlarged at its base and tapering uni- 

 formly to a free extremity on which is placed the mouth 

 opening. This opening is very small, although capable of 

 considerable expansion and extension and has thin lips. It 

 bears no tentacles on its edges. Tentacles are absent from 

 the base of the polypite. The cavity of the polypite serves 

 as a stomach and within it the half-digested food was ob- 

 served. This consists of smaller medusa^ and other small 

 marine animals, with unicellular algte. Velella is thought 

 to ])e omnivorous. 



The structures formed around the rim of the float on its 

 under side may be called the tentacles. They are long, 

 thread-like bodies, highly flexible, but not very contractile, 

 arranged in several rows, but never arising from the edge 

 of the umbrella. These tentacles are pointed and situated 

 a considerable distance from the edge of the umbrella as in 

 the young of V. muiica. They are covered with scattered 

 nematocysts in irregularly defined bands and disconnected 

 clusters. The tentacles are confined to the lower side of 

 the umbrella and lie on that part of the body which is un- 

 der the float. There are no appendages to that portion of 

 the uml)rella which is situated peripherally to the float. 

 Between the marginal tentacles and the central polyp there 

 hano- short stalks with botr3'oidal clusters of small buds 

 hano^ing from the lateral branches. These buds are mi- 

 nute medusa, or sexual clusters, each one of which lives a 

 considerable time after it breaks away from its attachment. 



Each medusa, of which many Avcre raised into the adult 



