2 3 2 



Phthinobranchii 



there are nine or ten dorsal spines and the body is more slender. 

 All kinds of waters of the north on both continents may yield 



FIG. 182. Three-spined Stickleback, Gasterosteus aculeatus L. Wood's Hole, Mass. 



this species or its allies and variations, mailed or naked. The 

 naked, Apeltes quadracus, is found in the sea only, along the 

 New England coast. 



Eucalia inconstans is the stickleback of the clear brook 

 from New York to Indiana and Minnesota. The male is jet 



FIG. 183. Four-spined Stickleback, Apeltes quadracus Mitchill. Wood's Hole, Mass 



black in spring with the sheen of burnished copper and he is 

 intensely active in his work of protecting the eggs of his own 

 species and destroying the eggs and fry of others. Spinachia 

 spinachia is a large sea stickleback of Europe with many dorsal 

 spines. 



No fossil Gasterosteida are recorded, and the family, while 

 the least specialized in most regards, is certainly not the most 

 primitive of the suborder. 



The Aulorhynchidae. Closely related to the sticklebacks is 

 the small family of Aulorhynchida, with four soft rays in the 



