130 



C(ELENTEBATA 



2. Dactylometra Agassiz. Forty marginal tentacles; 8 rhopalia; 

 48 marginal lobes: 5 species. 



D. quinquecirrha (Desor). Diameter uj) to 25 cm.: Long Island 

 and Vineyard Sounds to the tropics. 



Family 2. CYANEIDAE. 



Large disc-shaped medusae; radial pouches of the gastrovascular 

 cavity very wide and ramifying at their distal ends; no ring canal and 



no subgenital pouches: 4 genera, con- 

 taining the largest medusae; 6 species. 

 Cyanea Peron and Lesueur. Eight 

 groups of very long tentacles which ex- 

 tend from the subumbrella; oral lobes 

 very long, wide, and voluminous, between 

 which and the tentacles are the 4 large 

 bunches of gonads which have evagi- 

 nated from the gastrovascular cavity; 

 8 rhopalia in as many marginal indenta- 

 tions: 2 species. 



C. capillata (L.) var. arctica Per. and 

 Les. (Fig. 215). Disc usually 10 to 50 

 cm. in diameter, but specimens 2 m. in 

 diameter have been seen with tentacles 40 m. long; color variable, usually 

 purplish red or brown ; the largest jellyfish : common from North Carolina 

 to Greenland; a light-brown variety called C. fulva Agassiz occurs in 

 Long Island Sound, and a bluish-white variety called C. versicolor Ag. off 

 the Carolina coast. 



Fig. 215 — Cyanea capillata var. 

 artica (Mayer), showing the sub- 

 umbrella with the tentacles and 

 the oral lobes partly removed. 1, 

 oral lobe ; 2, gonad ; 3, tentacles. 



Family 3. ULMARIDAE. 



Radial canals nar- 

 row and branching, 

 forming a complex sys- 

 tem with a circular 

 canal joining the distal 

 ends: 10 genera and 17 

 species. 



AuRELiA Peron 

 and Lesueur. Oral 

 lobes long and rather 

 narrow; marginal ten- 

 tacles minute; body flat 



Fig. 216 — Aurelia aurita var. flavidula (Mayer). 

 s, subgenital pockets ; o, oral lobes. 



and disc-like; 4 large subgenital pockets; B 



rhopalia in as many marginal indentations: 5 species. 



