284 



ZOOLOGY. 



of concentrated salt water on railroad bridges in New En- 

 gland. Artemia fertilis Verrill abounds in Great Salt Lake. 



front view, a, 

 ovisac. 



Pig. 245. Thamnocephalus plalyurus, male, natural size, side and 

 head of the female ; b, end of the body of the female, showing the 



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

 Fig. 248. This species has a Nauplius young like that of 



Fig. 246.Sranchinec(es Cd&radensis Pack. 



the brine-shrimp of Europe (Fig. 244 J). It is a signifi- 

 cant fact, bearing 1 on the question of the origin of species, 

 that, according to Schmankiewitsch, Artemia may change its 



