THE LAMPREYS 



59 



as in Fig. 72, A, and then drawn in by stout tongue 

 muscles, T (Fig. 69) ; its digestive tube is almost straight, 

 terminating at the base of the tail region at A ; the 

 region of the gullet, OE, is pierced by a number of 

 branchial openings, varying from seven to fifteen, often 

 assymmetrical. The body cavity is an extremely large 

 one for the size of the contained viscera. An unpaired 

 fin, supported by delicate, unbranched (dermal) rays is 

 restricted to the hindmost part of the body. Passing 

 down the side is a row of mucous pouches by which a 

 remarkable supply of slime is secreted. The living animal 

 is enabled, by the peculiar character of this slimy secre- 

 tion, to render a pailful of water jelly-like in consistency. 



Bclellostoma occurs plentifully in the bays of the Pacific 

 coast of America, notably at Monterey, California. It is 

 active in its movements, is carnivorous, and is well known 

 to take a baited hook. Its numbers make it an enemy of 

 the fishermen, entangling and sliming their set lines, and 

 destroying the captured fish. It is said to feed at night, 

 although little is yet known of its general habits of living. 

 None but adult specimens have thus far been observed. 



The Hagfish, Myxine glutinosa (Fig. 71, and 72, B}, is in 

 many regards similar to Bclellostoma ; it differs mainly in 

 the character of its unpaired fin and in its branchial struct- 

 ures (Figs. 9, 10). As already noted, the outer ducts of the 

 gills, instead of opening separately at the surface as in 

 Fig. 70, are drawn together tail-ward, and terminate on 

 either side in a common ventral opening (Fig. 71, at the 

 point*). The unpaired fin is almost lacking in supports; 

 its ventral origin is even as far forward as the branchial 

 openings ; the anus, as a slit-like opening, pierces it in 

 the tail region. As in Bdellostoma, the nasal canal begins 

 at the snout, and at its hinder opening pierces the roof of 



