694 



FISHES. 



caudal. Maxillary lamina with four sharp flat lobes ; a pair of 

 long pointed lingual teeth. 



Two species, one from Chile and one from South Australia. 

 They grow to a length of two feet, and in some specimens 

 the skin of the throat is much expanded, forming a large 

 pouch. Its physiological function is not known. The cavity 

 is in the subcutaneous cellular tissue, and does not com- 

 municate with the buccal or branchial cavities. Probably it 

 is developed with age, and absent in young individuals. In 

 aU the localities in which these Extra-european Lampreys 

 are found, Ammocodes forms occur, so that there is little 

 doubt that they undergo a similar metamorphosis as P. 

 hranchialis. 



Second Family — Myxinid/e. 



Body eel-shaped, naked. The single nasal aperture is above 

 the month, quite at the extremity of the head, tvhich is provided 

 with four pairs of harhcls. Mouth without lips. Nasal 

 duct ivithout cartilaginous rings, penetrating 

 the palate. One median tooth on the palate, 

 and two comh-like series of teeth on the tongue 

 (see Fig. 101). Branchicd apertures at a 

 great distance from, the head; the iniier 

 branchial ducts lead into the esophagus. A 

 scries of mucous sacs along each side of the 

 ahdotncn. Intestine ivithout spiral valve. 

 Eggs large, with a horny ease provided with 

 threads for adhesion. 



The fishes of this family are known by 



^i^^^:^: 



Fig. 319.— OvTun of ^ ^^ ^. , „ ^- . ^^ „ 



Myxiue giutiuosa, the namcs of " Hag-Fish, " Glutinous Hag, 



enlarged. or "Borer;" they are marine fishes with a 



similar distribution as the Gadida^, being most plentiful in 



the higher latitudes of the temperate zones of the northern 



and southern hemispheres. They are frequently found buried 



