Phthinobranchii 447 
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 
t 
Fig. 351.—Three-spined Stickleback, Gasterosteus aculeatus L. Woods Hole, Mass. 
this species or its allies and variations, mailed or naked. The 
naked, A peltes quadracus, is found in the sea only, along the 
New England coast. 
Eucalia tnconstans is the stickleback of the clear brook 
from New York to Indiana and Minnesota. The male is jet 
Fig. 352.—Four-spined Stickleback, A peltes quadracus Mitchill. Woods 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. Spznachia 
spinachia is a large sea stickleback of Europe with many dorsal 
spines. 
No fossil Gasterosteide are recorded, and the family, while 
the least specialized in most regards, is certainly not the most 
primitive of the suborder. 
The Aulorhynchide.— Closely related to the sticklebacks is 
the small family of Aulorhynchide, with four soft rays in the 
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