28 The Irish Naturalist. February, 



jar along with Chrysaora, but it never attempted to catch 

 them. Copepods and other Crustacea were placed in the bell- 

 jar, but the medusa did not eat them. It seems clear that 

 Chrysaora mainly lives upon jelly-fish, using the term in a 

 popular sense. 



The long marginal tentacles are used for catching animals, 

 and the lightest touch is sufficient to hold securely a small 

 jelly-fish. The tentacle is then drawn up and towards the 

 frill of one of the oral arms ; the frill seizes the captured 

 medusa and passes it up into the mouth. When Chrysaora 

 was hungry it stretched out the tentacles to an enormous 

 length and also the frilled arms ; but when quite satisfied it 

 kept both contracted. A good meal consisted of several 

 dozen medusae and ctenophores. 



The water in the large bell-jar was changed daily, about 

 one gallon removed and a fresh supply added. The tempera- 

 ture of the water in the bell-jar was often taken and compared 

 with the surface temperature of the sea. The bell-jar stood on 

 a table near a window with an eastern aspect, sheltered from the 

 sun. In the early part of the year the water in the aquarium 

 was below the surface temperature of the sea. In February as 

 much as 3 to 5 degrees (sea minimum 47*5° F. ; aquarium 42 

 F.) In March the temperature became more equalized, and 

 later on the water in the aquarium was above the tempera- 

 ture of the sea. During May and June the aquarium was 

 usually about 3-4 degrees in excess (aquarium 59°-62° F.) In 

 July there was a short spell of hot weather, which increased 

 the temperature of the aquarium to 66°F., the sea being 64 F. 

 This was the highest temperature recorded in the aquarium. 



Valencia, Co. Kerry. 



EXPLANATION OF PLATES. 



Pirate i. 

 Fig. 1. Chrysaora isosceles— Scyphistoma stage, x 25. 

 ,, 2. A Scyphistoma beginning to strobilize, x 25. 

 ,, 3. Strobila stage, showing Ephyrse ready for liberation, x 25. 

 ,, 4. Young Ephyrse just liberated, x 10. 



Plate 2. 

 Fig. 5. An Ephyra, oral view, X 35. 

 ,, 6. An advanced Ephyra, three weeks :>ld, x 2\. 

 ,. 7. An advanced Ephyra, four weeks old, x 2$. 



