SFCT. in. APOLEMIA CONTORT A. 109 



cone with the float at its apex. The bells are flattened ; 

 and there is always in their more solid posterior part a 

 single canal rising directly from the general trunk which 

 divides into four branches ; and these, having traversed 

 the swimming cavity, unite anew in a circular canal, 

 or iris, destined to shut and open the cup. 



The sterile polypites that are attached at intervals by 

 their hollow stems to the twisted body of the Apolemia, 

 have twelve rows of cells inserted in the bright lining of 

 their digestive cavities ; their anterior part has a trumpet- 

 shaped mouth full of thread-cells. The tentacles amxed 

 to their stems and their secondary lines are like those 

 of the Diphyidse. Besides these sterile polypites, which 

 serve only to feed the animal, the Apolemia has a kind 

 of mouthless prolific organs, which do not contribute 

 to the general nourishment : each group has a pair of 

 them attached to the extremity of a branching stem. 

 They resemble polypites in being long and contractile 

 at their extremities ; the interior is full of a substance 

 like sarcode, and encompassed by a red ring. Female 

 buds yielding eggs appear on the stem of one of these 

 organs, while male buds are developed into medusiform 

 zooids on the stem of the other, which become detached, 

 swim away, and the fertilized eggs yield young Apo- 

 lemise. 



The natural position of an individual of the family of 

 the Physophoridse when at rest is to hang perpendicu- 

 larly from its air-vessel. The body, which begins with 

 a pyriform float, descends in a slender filiform scarlet 

 tube with a number of hyaline natatory cups or bells 

 attached on each side. The lower end of the body en- 

 larges into a bulb or disk supporting various appen- 

 dages. 



The Physophora hydrostatica (fig. 120), common in 

 the Mediterranean, has a transparent pear-shaped air- 

 vessel tipped with red, from which the slender cord-like 



