ACALEPH.E. 



233 



great number of tentacles, the exterior ones being longest, and also 

 with small cilia, each terminating in a globule, which sometimes 

 contains air ; the interior tentacles are shorter, simple, and fleshy. In 

 the centre of these tentacula is the mouth, in form of a small proboscis, 

 leading to a simple stomach surrounded by a somewhat glandular 

 substance. The editors of the last edition of the " Kegne Animal " 

 only mention one species P. Gigantea, a native of the Mediterranean 

 and other warm seas, of a beautiful blue colour. Lamarck gives four 

 species. De Blainville and others consider with Guvier that they are 

 only varieties, which Eschscholtz reunites under one species. In 

 Fig. 94 we have represented P. Pacifica (Lesson), the disk of which is 

 twelve lines in diameter, 

 without comprehend- 

 ing the tentacles. This 

 disk is finely radiated 

 on the under surface 

 with a brilliant argen- 

 tine nacre. The mem- 

 branous fold which sur- 

 rounds it is cut into, 

 leaving light and per- 

 fectly straight festoons. 

 It is of a clear celestial 

 blue colour, and very 

 transparent. The ten- 

 tacles are much com- 

 pressed, very thin and 

 cylindrical, of a light 

 blue, and the glands are of an indigo blue colour. All the repro- 

 ductive individuals, which are placed in the lower part of the body, 

 are of a perfect hyaline white. 



This beautiful Porpita was discovered by Lesson on the Peruvian 

 coast, where it occurs in swarms closely packed on the surface of the 

 sea. " Its manner of life," says Lesson, " is perfectly analogous to 

 that of the Yilella. Their locomotion on the sea is purely passive, at 

 least in appearance. Their disk laid flat on the surface upon the 

 water-line, leaves them to float freely and in a horizontal direction, 

 the irritable arms hanging all round them." 



Fig. 94. Porpita pacifica (Lesson). 



