Ill 



THE LAKE DISTRICT 



81 



great group of sessile-eyed Crustacea, the Amphi- 

 poda. The Phreatoicus of the Great Lake belong 

 to several distinct species and are exceedingly 

 abundant ; one species is very large, sometimes 

 attaining to an inch in length, and is adorned with 

 spines, while the antennae and extremities are of 

 a brilliant orange colour (Fig. 19). These animals, 

 which are without any closely related forms in 

 any other part of the world, are very sluggish 



Fig. 19. Phreatoicus spinosus, from the Great Lake. 

 (Three times natural size. ) 



in their habits, and they appear to live rather 

 after the manner of Earthworms, passing a great 

 quantity of vegetable mud through the intestine, 

 which is thrown into elaborate folds to increase 

 its absorptive area, just as in the Earthworm. 



It is thus seen that the two most abundant 

 Crustaceans of the Great Lake, Paranaspides and 

 Phreatoicus, are highly peculiar forms standing in 

 somewhat the same relation to the other Crus- 

 tacea as the Platypus does to ordinary mammals. 

 Besides these, living with them in the same littoral 



SMITH : N.T. 



F 



