4 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY - IV. 



( ),an:n B.-IIYTEROTRETA. 



(Tin- M i/.r! iioi<l Fin 



Nostril tube-like. with cart ilaginous rings, penetrating tlio palate, its 

 ])osiliiui nt tin- extremity <>!' the head, over the mouth : snout with eight 

 harltels; moiitli \vithoutlips; one median tooth on the palate and two 

 comb like series of teeth on the tongue. Jiranchial a]>erttires at a great 

 distance from the head : a series of mucous sacs along each side of the 

 abdomen. Intestine without spiral valve. Eggs large, with a hornr 

 case provided \vith threads lor adhesion. Marine lamprey-like animals, 

 lull-rowing into the tlcsh of fishes, on which they feed. 



There is but oir. family, Mi/.i'ii/idtc, unless we assign separate rank to 

 rl<-U<>*tom<( on account of the difference in the gill-openings. (u-ef>u>a, 

 palate; -r,r.>, perforate.) (Family Mi/.i-iiiidir Giintlier, 510-511'.) 



FAMILY II MYXINID^E. 



(The nag-fish^.} 



The characters of the family are included above. Genera two; species 

 few ; marine animals, found in all temperate seas. (Mi/.cini<l<r Giintlier, 

 viii, 510-511*. 



mdiial aprrtun-s our on i-:idi siilr. l':ulinn l>y six ducts to six br:mclii:il snrs. 



MYXINK, ','. 



* I'.raiidiial aprrt urcs six or mon- on cadi side, each leading direct ly tu a luandiial 

 ........................................................... BDELLOSTOMA, 3. 



2. HYXIIVK Linna-ns, 17.")8. 



Hag-fishes. 



(Lilin:i-ii-.. Sy-lrina \alur:r: t\|>c Mij.,iii< t/liiliiinxd L.) 



I'.ody eel slmped. covered by a thin skin, which is easily detached. 

 . \loii; the lo\\er side, for nearly the whole length of the animal, are, 

 t\\o rows of mucous glands, each \\ith an external opening, from which 

 - a quantity of mucus which renders these animals during life 

 xj\ ,-|\ >lini\. No eyes. Pirain small, of the normal lish type. 

 Skull little de\doped. cai-tilauiiious: the llexible notochord enclosed in 

 -heath, and extending from the base of the skull to tllC Clld of the 



