CHARACTERISTIC DEEP-SEA TYPES. ACALEPHS. 131 



pointed conical bell, widening below into a funnel-shaped mar- 

 gin, the upper and lower parts of the bell being divided into 

 well-marked regions separated by a characteristic furrow. The 

 margin is formed by a number of gelatinous blocks closely fitted 

 together, which serve as supports for important organs called 

 socles. These support tentacles, marginal sense bodies, and thin 

 leaf-shaped lappets which have given the genus its name. The 



Fig. 425. — Dodecabostrycha dubia. ^. 



stomach hang-s down from the under side of the bell, and in its 

 spacious receptacles are found prominent filaments. The color is 

 blue. The American species P. hyacmthina (Fig. 426) extends 

 as far north as the coast of Greenland. 



None of these so-called deep-sea medusae, however, present 

 such remarkable features as the species of Atolla. The genus 

 has thus far been taken by the " Challenger " in the Antarctic 

 Ocean, on the borders of the South Atlantic and South Indian 



