Dr. F. Miiller on Philomedusa Voatii. 435 



c 1 



on the hinder part of the body, alternating with the longitudinal 

 furrows. Their number increases with age, and rises, in the 

 largest specimens, to about twenty in each row. Their diameter 

 varies: the largest orifice that I have met with was 0/1 millim. 

 in length, and half that breadth. Under the microscope, the 

 minute particles driven about by the cilia of the body-cavity 

 may sometimes be seen to issue from them. They are of course 

 closed by the contraction of the wall of the body, but are also 

 capable of contracting and closing independently : when con- 

 tracting, they appear to be surrounded by a pale space; and 

 when closed, a pale spot appears in their place. 



The middle of the posterior extremity is completely closed in 

 the animal when filled with water ; but on rapid contraction, a 

 wide orifice for the escape of the water opens at this point *, 

 through which portions of the mesenteric frills not unfrequently 

 pass at the same time. In a large specimen which I put into a 

 test-tube in order to observe it more conveniently, I saw, after 

 it had distended itself again with water, a slender cord stretched 

 tightly from the end of one of the longer mesenteric frills to the 

 middle of the posterior extremity, which, as I knew, was not 

 there before. After a fresh slight contraction of the animal, 

 caused by shaking the glass, the cord began to remove from the 

 posterior extremity, and contracted itself with extraordinary 

 slowness, still retaining its straight form : thus it proved itself 

 to be a fragment of the mesenteric frill in question, which had 

 been fixed during the first contraction, and set free by the open- 

 ing of the terminal orifice caused by the second contraction. 



I first found Philomedusa Vogtii adhering singly to the lower 

 surface of the disk in Olindias (nov. gen. Eucopidarum) , and 

 subsequently in plenty upon Chrysaora, in which it dwells on the 

 arms, in the sexual cavities, and in the stomach and its sacs. 

 From a single Medusa of the last-named genus I have removed 

 more than twenty of these Polypes. The animals taken from 

 the Medusae usually have fragments of the tentacular filaments, 

 genitalia, stomachal filaments, &c, of the host in their stomachs ; 

 and urticating capsules of the Medusa are often met with in the 

 body-cavity of the Polype. Like the Actiniae, they bear captivity 

 well ; they will do without food for months, and will also take 

 other food besides parts of Medusse, exhibiting a preference 

 for Annelides. If a large number be kept in the same vessel, 



* This is also the case in Cerianthus (Jules Haime, in Ann. des Sc. Nat. 

 ser. 4. tome i. p. 341), with which polype that above described has much 

 affinity. The number and especially the position of the tentacles certainly 

 does not agree, as Cerianthus possesses a double and Philomedusa a single 

 row of tentacles. However, with regard to their systematic position, it 

 must be borne in mind that the animals, as above stated, have not yet been 

 observed in a state of sexual maturity (Max Schultze). 



