58 ANIMALS OF THE SEASHORE 



Blackfortia manhattensis Mayer 



Distinguished from the above chiefly by the ab- 

 sence of the dark pigment granules adjacent to the 

 lithocysts. Originally described from off Sandy 

 Hook, New Jersey, where it was said to be common 

 during October. 



Aequorea groenlandica Peron and Lesuer 

 (Zygodactyla groenlandica P. & L.) 



Fig. 3 

 Aequorea groenlandica Peron and Lesuer 



This is the largest American hydromedusa and 

 may reach a foot in diameter although its more 

 normal size is about 6 inches. Very many radial 

 canals. 



A northern species usually found north of Cape 

 Cod; occasionally found in New Jersey waters 

 especially after storms. 



Siphonophores 



Free-floating communities made up of different 

 types of individuals, each performing different func- 

 tions in the community. 



