230 



ACTINOZOA. 



in learning, but in unlearning, is the student of 

 the Ctenophora compelled to waste his time and 

 ingenuity. 



Some Ctenophora are phosphorescent. In a 

 species of Bolina common around our shores this 

 beautiful property may very readily be observed. 

 Specially distinguished for its luminosity is the 



much larger Cestum Veneris of the Mediterranean, 



which is said to gleam at night like a brilliant 

 band of flame, moving beneath the surface of the 

 water. 



By Gregenbaur the Ctenophora have been di- 

 vided into five families, which may be defined as 

 follows : — 



Order CTENOPHOKA, 



Sub-order i. Stenostomata. 



Family i. CALLYMMiDiE. 



Body furnished with a pair of anteropos- 

 terior oral lobes, and other smaller lateral 



appendages. Tentacles various, turned to- 

 wards the mouth. 



Family 2. Cestim:. 



Body ribbon-shaped, extended in a lateral 

 direction, without oral lobes. Tentacles two 

 in number, antero-posterior, turned towards 

 the mouth. 



Family 3. Callianirid^e. 



Body produced into a pair of wing-like, 

 lateral lobes, bearing the ctenophores. Ten- 

 tacles two in number, lateral, turned from 

 the mouth. 

 Family 4. Pleurobrachiadj:. 



Body oval or spheroidal, without oral 



