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The Scyphophori, Haplomi, and Xenomi 423 
much resemble the mud-minnows, differing mainly in the very 
broad pectorals. But the skeleton is thin and papery, the two 
coracoids forming a single cartilaginous plate imperfectly divided. 
The pectorals are attached directly to this without the inter- 
vention of actinosts, but in the distal third, according to 
Dr. Charles H. Gilbert, the coracoid plate begins to break up 
Tic. 333.—Alaska Blackfish, Dallia pectoralis (Bean). St. Michaels, Alaska. 
into a fringe of narrow cartilaginous strips. 
“In the deep-sea eels of the order Heteromi there is a some- 
what similar condition of the coracoid elements inasmuch as 
the hypercoracoid and hypocoracoid though present are merely 
membranous elements surrounded by cartilage and the acti- 
nosts are greatly reduced. It seems probable that we are 
dealing in the two cases with independent degeneration of the 
shoulder-girdle and that the two groups (Xenomi and Heteromt) 
are not really related.”’ (Gilbert.) 
Of the single family Dalliide, one species is known, the 
Alaska blackfish, Dallia pectoralis. 
This animal, formed like a mud-minnow, reaches a length 
of eight inches and swarms in the bogs and sphagnum swamps of 
northwestern Alaska and westward through Siberia. It is found 
in countless numbers according to its discoverer, Mr. L. M. 
Turner, ‘““wherever there is water enough to wet the skin of 
a fish,’ and wherever it occurs it forms the chief food of the 
natives. Its vitality is most extraordinary. Blackfishes will 
remain frozen in baskets for weeks and when thawed out are 
as lively asever. Turner gives an account of a frozen individual 
swallowed by a dog which escaped in safety after being thawed 
out by the heat of the dog’s stomach. 
