SCYPHOZOA 



127 



Key to the genera of Lucernariidae here described : 



c x Adhesive pads absent 1. LUCEBNABIA 



a 2 Adhesive pads present. 



61 Stalk quadrate 2. HALICLYSTUS 



6 2 Stalk cylindrical 3. HALIMOCYATHUS 



1. LUCERNARIA 0. F. Miiller. Marginal adhesive pads absent; stalk 

 cylindrical: 8 species, 1 American. 



L. quadricornis Mull. Height 7 cm.; diameter 5 cm.; color green, 

 gray, or reddish; tentacles on each lobe 100 or more: Cape Cod to 

 Greenland; Europe. 



2. HALICLYSTUS Clark. Eight 

 marginal adhesive pads between 

 the lobes; stalk quadrate: 6 spe- 

 cies, 2 American. 



H. auricula Clark (Fig. 209). 

 Height and diameter 3 cm.; color 

 variable; tentacles on each lobe 

 100 or more: Cape Cod to Green- 

 land; Europe; Alaska. 



H. salpinx Clark. Height 20 

 mm.; diameter 25 mm.; tentacles 

 slender, about 70 on each lobe; 

 marginal pads very large and as 



long as the tentacles: Cape Cod to Fjg 20a _ Haltcllistus auricula (Mayer) . 

 Greenland; Adriatic Sea. 



3. HALIMOCYATHUS Clark. Marginal adhesive pads present; 4 

 gastrogenital pockets present in subumbrella wall of the gastrovascular 

 pouches; stalk cylindrical: 2 species. 



H. lagena (Haeckel). Height 3 cm.; diameter 7 mm.; tentacles on 

 each lobe 70: Cape Cod to Greenland; rare; Europe. 



ORDER 2. CORONATAE. 



Medusa with a constriction about its middle; margin in most cases 

 with 16 lobes, long tentacles and rhopalia: 5 families and 27 species, 

 which are usually found in the open ocean. 



FAMILY 1. PEEIPHYLLIDAE. 



Marginal lobes 16; tentacles 4 or more; rhopalia 4: 4 genera and 

 8 species. 



PERIPHYLLA Steenstrup. Twelve tentacles; body conical; 4 deep 

 subgenital pockets (funnels); gonads horseshoe-shaped: 3 species. 



