thalassemad^e. 75 



Family III. Thalassemad^e. 



Thalassema (Cuv.). Body cylindrical, rounded 

 and smooth behind ; proboscis retractile, short, 

 furnished at one side with a long, fleshy, furrowed, 

 simple sheath, which is not retractile. 



T. Neptuni. Fig. 122 ; n. s. 



Echiurus (Cuv.). Body cylindrical; set at its 

 hinder extremity with circles of horny points ; pro- 

 boscis as in Thalassema. 



E. oxyurus. Fig. ]23; I. 



