GEN. ECHENEIS. SUCKING-FISH. 255 



above the upper lip, extending nearly as far as the 

 ends of the pectoral fin rays. The fins are all 

 covered with a leathery membrane. " The vertical 

 direction of the moveable laminag," says Mr. Yarrell, 

 in reference to the adhesive apparatus, " is efi'ected 

 by sets of muscles going off obliquely right and left 

 from two elongated bony processes, one on each half 

 of each of these moveable divisions. The contrac- 

 tion of these muscles, acting upon these levers, raises 

 the external edges of the parallel divisions, increas- 

 ing the area of the vacuum ; and it will be observed 

 that the points of the moveable transverse divisions 

 to which the muscles are attached are nearer the 

 middle line than the outer edge, by which the chance 

 of interfering with the perfect continuity of the free 

 margin, and thereby destroying the vacuum, is di- 

 minished. All the bony laminag, the outer edges of 

 which are furnished with rows of minute tooth-like 

 projections, are moved simultaneously, like the thin 

 vertical divisions of our common wooden window- 

 blinds, by means of the mechanical contrivance on 

 the framework. The longer muscles, placed near 

 the outer oval edge, are probably instrumental in 

 preserving the contact of the more flexible margin, 

 and the serrated external edges of the parallel la- 

 minae help to preserve the degree of elevation ob- 

 tained : the adhesive power is in proportion to the 

 area of the" vacuum." * 



* British Fishes, vol. ii p. 379. 



