304 



ZOOLOGY. 



of concentrated salt water on railroad bridges in New En- 

 gland. Arteinia fertilis Verrill abounds iu Great Salt Lake. 



Fig. 250. — Thnninocephalus X)latyurus,mi\\e,i-\&\n\-a.\ size, side and front view, a, 

 head of the female ; 6, end of tlie body of ttie female, showing the ovisac. 



They may often be seen swimming about in pairs, as in 

 Fig. 353. This sf)ecies has a Nauplius young like that of 



Branchifwcleb- Coloradai^iU Paclv. 



the brine-shrimp of Europe (Fig. 249 l). It is a signifi- 

 cant fact, bearing on the question of the origin of species, 

 that, according to Schmankiewitsch, Artemia may change its 



