The Cyclostomes, or Lampreys 169 
ate; rperos, perforate), or hagfishes, have the nostril highly 
developed, a tube-like cylinder with cartilaginous rings pene- 
trating the palate. In these the eyes are little developed and 
the species are parasitic on other fishes. In Polistotrema stouti, 
the hagfish of the coast of California, is parasitic on large fishes, 
rockfishes, or flounders. It usually fastens itself at the throat 
or isthmus of its host and sometimes at the eyes. Thence it 
works very rapidly to the inside of the body. It there devours 
all the muscular part of the fish without breaking the skin or 
the peritoneum, leaving the fish a living hulk of head, skin, and 
bones. It is especially destructive to fishes taken in gill-nets. 
The voracity of the Chilean species Polistotrema dombeyi is equally 
remarkable. Dr. Federico T. Delfin finds that in seven hours a 
hagfish of this species will devour eighteen times its own weight 
of fish-flesh. The intestinal canal is a simple tube, through 
which most of the food passes undigested. The eggs are large, 
each in a yellowish horny case, at one end of which are barbed 
threads by which they cling together and to kelp or other objects. 
In the California hagfish, Polistotrema stouti, great numbers of 
these eggs have been found in the stomachs of the males. 
Similar Habits are possessed by all the species in the two 
families, Myxinide and Eptatretide. In the Myxinide the 
Fie. 117.—California Hagfish, Polistotrema stouti Lockington. 
gill-openings are apparently single on each side, the six gills 
being internal and leading by six separate ducts to each of 
the six branchial sacs. The skin is excessively slimy, the ex- 
tensible tongue is armed with two cone-like series of strong 
’ teeth. About the mouth are eight barbels. 
