MYXINE. 497 



40 to 300 fathoms. It often lies buried with only the 

 nostril protruding from the mud, but it can swim gracefully 

 and rapidly in eel-like fashion in search of prey. It eats 

 the bait off the fisherman's long lines, and it also enters and 

 devours the cod, etc., which have been caught on the hooks. 

 According to some, the hag also bores its way into free- 

 swimming fishes, but the evidence is not satisfactory. Ac- 

 cording to Mr, T- T. Cunningham, the young animals are 

 hermaphrodite, containing immature ova and ripe sper- 

 matozoa, while older forms produce ova only. If the same 

 form is first functionally a male and afterwards functionally 

 a female, the term " protandrous hermaphroditism ' is 

 justified, and Nansen corroborated Cunningham's dis- 

 covery, which is, however, disputed by Bashford Dean. A 

 somewhat similar " protandrous " hermaphroditism is known 

 elsewhere, e.g. in the Nemertean Stichostemma eilhardii, in 

 the aberrant Myzostoma^ and in the crustacean Cymothoidae. 

 Hag are said to spawn in late autumn. Of the development 

 and early history nothing is known. 



Form, skin, and muscular system.- -The body is eel- 

 like, measuring 15 to 24 in. in the adult. The colour is 

 pinkish, the red blood shining through an unpigmented 

 skin. There is a slight median fin around the tail ; beside 

 the mouth and nostril there are four pairs of sensitive 

 barbules. There are no paired fins. The cloacal opening 

 is near the posterior end of the body. 



The skin is scaleless, and rich in goblet cells, which 

 secrete mucus. There is also a double row of glandular 

 pits, partly embedded in muscle, and arranged segmentally 

 on each side of the ventral surface along its entire length. 

 Each opens by a distinct pore, and so much mucus is rapidly 

 secreted that the ancients said the hag " could turn water 

 into glue." This makes the hag difficult to grip, and its 

 function is doubtless in part protective. The mucus chiefly 

 consists of strange spiral threads which uncoil when ejected 

 from the sacs. 



The zig-zag muscle segments or myomeres are traceable. 

 The rasping teeth are worked by a powerful muscular 

 structure, sometimes called a "tongue." A section 

 of this shows a strong muscular cylinder surrounding a 

 cartilage. 



32 



