Bulletin 47, United States National Museum. 



habits similar to those of Myxine glutinosa. They fasten themselves on 

 the gills or eyes or isthmus of large fishes, whence they work their way 

 very rapidly into the inside of the body. They there devour all the flesh 

 without breaking the skin, so that the fish is left a mere hulk of head, 

 skin, and bones. (Myxinidce, genus Bdellostoma, Giinther, Cat., vm, 511. 

 The generic name Heptatrema, Pum^ril, has priority over Bdellostoma.) 



a. Gill openings 10 to 12 on each side; base of tongue opposite sixth or seventh pair of gills. 



POLISTOTREMA, 3. 



3. POLISTOTREMA, Gill. 



Polistotrema, GILL, Proc. U. S. Nat. Mus., 1880, 30, (donibey}.* 



This genus is distinguished from Heptatrema (Bdellostoma) by the pres- 

 ence of 10 to 14 gill openings, instead of 6 or 7, as in Heptatrema. Two 

 or 3 species known, from the eastern Pacific. (A superlative of TroK'f, 

 many ; rpr/ua aperture.) 



5. POLISTOTREMA STOTJTI, (Lockington). 

 (CALIFORNIA HAGFISH; LAMPERINA.) 



Gills usually 1 12 on each side, the number varying from 10 to 14. Teeth 

 10 in each series. Branchial artery dividing opposite sixth or seventh 

 pair of gills. Snout 20 times in total length; head to first gill opening 

 4|; branchial region 8, tail 8. Plum color, paler below, the edge of the 

 lower fold pale. Skin thin, very lax, and separable from the muscles, 

 excessively slimy. L. 14 inches. Coast of California, and north to Cape 

 Flattery, very abundant about Monterey, burrowing t into the flesh of the 

 larger flounders and Sebastodes. (Named for Dr. A. B. Stout, of San Fran- 

 cisco.) 



Bdettostoma stouti, LOOKIN'GTON, Amer. Nat., 187s, 793, Eel River, California. 

 Bdellostoma dombey, JORDAN & GILBERT, Synopsis, 57, 1883, not of Cuvier. 



* Polislotrema dombey (Cuvier) is a species distinct from P. stoitti. It is thus characterized bv Put- 

 nam (Proc. Boat. Soc. Nat. Hist., 1873, 160), from specimens from Chile: " Head about % of total 

 length, and contained aboutl% times in the length of the abdomen. Tail 7 to 8 times in total 

 length. Base of tongue between the 7th or 8th pair of gills. Gills, 10 on each side. Length 

 from 13 to 22 inches. Coast of Chile." According to Putnam the branchial artery divides at its 

 base into a right and a left trunk in this species. 



Le Gastrobranche dombcy, LACEPEDE, Hist. Nat. Poiss., I, 531, 1798, Chile, non-binomial. 

 Gaslrobranchus dombey, CUVIER, Regne Animal, 121, 1817, after Lacepede. 

 Bdellostoma polytrema, GIRARD, Proc. Acad. Nat. Sci. Phila., 1854, 199, Valparaiso. 

 Bdellostoma polytrema, GUNTHER, Cat., vm, 512, 1870. 



fAccording to Dr. Gilbert, in 54 specimens of PoJislolrema siouti, 41 were found to have 12 gill 

 opening.- on each side, 12 had 11 on each side, and 1 had 13. Occasional specimens may have 

 either 10 or 14, but the normal number is 12. 



JThe hagfish fastens itself usually on the gills or isthmus of large fishes, sometimes on the 

 eyes, whence it works its way very rapidly into the inside of the body. It then devours all the 

 flesh of the body without breaking the skin, so that the fish is left a living hulk of head, skin, 

 and bones. It is especially destructive to fishes taken in gill nets. In every gill net in summer, 

 at Monterey, more or less of these empty shells of fishes are obtained. When these are taken 

 from the water the hagfish scrambles out with great alacrity. It is thought that the hags 

 enter the fishes after they are caught. A fish of 10 to 15 pounds weight will be devoured by 

 them in a single night. Large fishes of even 30 pounds weight are often brought up without 

 flesh and without viscera, and they certainly do not swim into a gill net in this condition. 



The fishes chiefly infested are Sebastodes pinniger, miniatus, and mystinus, Ophiodon elongatu? t 

 Paralichthys californicus, and Rhacochilvs toxotes. 



