26 MARINE AND FRESHWATER FISHES 



beneath the water, in what is known as the Laminarian 

 Zone. In this manner the numerous simple or lobulated 

 membraneous structures, dependent from the lower jaw, 

 and developed as a fringe along the lateral line of the 

 body, imitate with great fidelity the little flat calcareous 

 sponges (Grantias), small compound ascidians, and other 

 low-organised zoophytic growths that hang in profusion 

 from favourably situated submarine stones. That famous 

 structure, known as the angler's " rod and bait," finds 

 its precise counterpart in the early growing phase of 

 certain sea-plants such as the oar-weed (Laminaria), while 

 the more posterior dorsal fin rays, having short lateral 

 branchlets, counterfeit in a like manner the plant-like hy- 

 droid zoophytes, known as Sertularice. One of the most 

 extraordinary mimetic adaptations was, however, found in 

 connection with the eyes, structures which, however perfectly 

 the surrounding details may be concealed, serve, as a rule, 

 to betray the animal's presence to a close observer. In the 

 case of the Angler, the eyes during life are raised on 

 conical elevations, the sides of which are separated by 

 darker longitudinal stripes into symmetrical regions, the 

 structure as a whole, with its truncated summit upon which 

 the pupil opens, reproducing with the most wonderful 

 minuteness the multivalve shell of a rock-barnacle (Balanus). 

 To complete the simile the entire exposed surface of the body 

 of the fish is mapped out by darker punctated lines into irre- 

 gular polygonal areas, whose pattern is at once recognised 

 by the student of marine zoology as corresponding with 

 that of the flat, cushion-like expansions of the compound 

 tunicate, Botryllus violaceus. Thus disguised at every point, 

 the Angler has merely to lie prone as is its wont * among 



* The picture reproduced in even many recent popular Natural 

 History Works of the Angler poised tranquilly in mid-water, fishing for 



