COMMON REMORA. 379 



The fin-rays in number are 



D. 21 : P. 22 : V. 4 : A. 20 : C. 20. 



The colour is dusky brown ; the under part of the body 

 rather lighter than the back ; the fins darker in colour than 

 the body. 



The disk of the adhesive apparatus in the specimen now 

 described with seventeen transverse laminse was one-third 

 of the whole length of the fish, not including the caudal 

 rays ; the breadth one inch and one quarter. The figure 

 on the left side of the vignette represents the outer surface 

 of the anterior half of the disk : the margin is free, flexible, 

 and of considerable breadth, to secure perfect contact with 

 the surface to which it is opposed ; the parallel laminse are 

 represented as only slightly elevated ; the degree of adhesion 

 is in proportion to the power used to raise the inner surface 

 of the disk in a direction perpendicular to the plane of con- 

 tact. The figure on the right side of the vignette represents 

 the inner surface of the posterior half of the disk. The ver- 

 tical direction of the moveable laminse is effected by sets 

 of muscles going off obliquely right and left from two elon- 

 gated bony processes, one on each half of each of these move- 

 able divisions. The contraction of these muscles, acting 

 upon these levers, raises the external edges of the parallel 

 divisions, increasing 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 de- 

 stroying the vacuum, is diminished. All the bony laminse, 

 the outer edges of which are furnished Avith rows of minute 

 tooth-like projections, are moved simultaneously, like the 

 thin vertical divisions of our common wooden window-blinds 



