188 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



There are two specimens of this medusa in the Albatross collec- 

 tion from the Philippines. They are apparently mature and their 

 dimensions in millimeters are as follows : 



Subig Bay, 

 Luzon, sur- 

 face, Jan. 6, 

 1908. Cat. 

 No. 27937, 

 U.S.N.H. 



Height of bell I 34 



Width of bell 20 



Length of pedalia j 11 



Width of pedalia at base 



Width of pedalia at widest part ' 6. 5 



Height of sensory niche above velar margin j 6 



Length of flexible shafts of tentacles ' 30 



Taal Anchor- 

 age, Balayan 

 Bay, Luzon, 

 surface, Feb. 

 20, 1909. 

 Cat. No. 



28714, 

 U.S.N. M. 



33 

 23.5 



9.5 



4 



5.5 



6 

 66 



Two other specimens (Cat. No. 27935, U.S.N.M.) were taken by 

 the Albatross at Nasugbu, Luzon, January 15, 1908, and still another 



(Cat. No. 27936, U.S.N.M.) at Mansalay, 

 Mindoro. 



This is the commonest Cubomedusa of 

 the tropical Pacific, being widely distrib- 

 uted from South Australia to the Ha- 

 waiian Islands. It can be recognized by 

 its prismatic, 4-sided bell, the 4 pedalia 

 being about one-fourth to one-third as long 

 as the bell-height, flat and spatula-shaped 

 and about three-fifths as wide as long. The 

 sense-clubs have each 2 large median eyes 

 and 4 small lateral ocelli. There are 4 

 short, branched, non-anastomosing velar 

 canals in each quadrant of the velarium, 

 16 in all. Four very small branched tufts 

 of gastric cirri. This medusa is very 

 closely allied to Garybdea marsupialis of 

 the Mediterranean, but is distinguished by 

 having only 16 instead of 24 to 30 velar canals, and by its somewhat 

 more slender pedalia. In both forms the bell is dull milky yellow 

 and the flexible parts of the tentacles are pink. In common with 

 other Cubomedusae it comes to the surface when mature and is then 

 abundant in harbors. The young usually remain in deep water at 

 or near the bottom. 



Fig. 2. — Carybdea rastonii 

 from the Hawaiian 

 Islands. Two views of 

 its sense-clubs and a 

 quadrant of the velarium, 

 showing the branched 

 velar canals. 



