284 



ZOOLOGY. 



of concentrated salt water on railroad bridges in New En- 

 gland. Artemia fertilis Verrill abounds iu Great Salt Lake. 



he 



Fig. 245. Thamnocephalus platy urn*, male, natural six.e. side and front view, o, 

 ;ad of the female ; 6, end of the body of the I emale, showing the ovisac. 



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

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



Fig. 2l.Bmnchinectes Colorademis Pack. 



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

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

 that, according to Schmankiewitsch, Aiii'inia may change its 



