168 FRESHWATER FAUNA 



coelis, Mesostoma, Prorhynchus. CCELENTEBATA : Hydra 

 (Fig. 49) and Cordylophora. SPONGES : Spongilla, 

 Ephydatia. 

 PROTOZOA : INFUSORIA, EHIZOPODA. 



On first glance at this list we notice that among the 



FIG. 48. A Polyzoan, Plumatella fungosa, 

 Pallas. Two individuals with extended 

 tentacles. a. Tentacles. b. Tentacle 

 carrier, c. Tentacle sheath, d. Gullet. 

 e. Stomach. /. Intestines, g. Funiculus. 

 h. Muscle. Magnified 20 diameters. 

 After Vosseler, from Lampert, ' ' Das Leben 

 der Binnengewasser." 



Invertebrata whole groups of marine forms are missing ; 

 the Echinodermata, of which that common object on the 

 seashore, the reluctant starfish, is an example, are wholly 

 unrepresented : so are the Brachiopoda, best known to 

 us in this country by their fossil forms, such as Terebratula 

 and Ehynchonella, so abundant in our stratified rocks : 



