294 LOWER VERTEBRATES. 



the direction of concealing the identity of her protege, such ingenuity being some- 

 times utilized with the object of protecting the organism from the attacks of other 

 animals, or, as illustrated in the present instance, for the purpose of enabling it by 

 stealth to obtain prey, which it lacks the agility to hunt down after the manner of 

 ordinary carnivorous fishes. To recognize the several details here described, it will not 

 suffice to refer to examples simply — and usually most atrociously — stuffed, nor even 

 to those preserved in spirit, in which all the life colors are more or less completely 

 obliterated, and the various membranous appendages shrunk up and distorted. In 

 place of this, a healthy living example fresh from the sea, or, better still, acclimatized 

 in the tanks of an aquarium, must be attentively examined, and whereupon it will 

 be found that this singular fish, throughout the whole extent of its superficies, may be 

 appropriately designated a living sham." It was, in the first place, observed by Mr. 

 Kent, " that the fish, while quietly reclining upon the bottom of its tank, presented a 

 most astonishing resemblance to a piece of inert rock, the rugose prominences in the 

 neighborhood of the head lending additional strength to this likeness. This resem- 

 blance being recognized, it was next found, on a little closer inspection, that the fish 

 constituted, in connection with its color, ornamentations, and manifold organs and 

 appendages, the most perfect facsimile of a submerged rock, with that natural clothing 

 of sedentary animal and vegetable growths common to boulders lying beneath the 

 water, in what is known as the Laminavian zone. In this manner the numerous 

 simple or lobulated membranous 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 

 organized zoophytic growths that hang in profusion from favorably 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 

 (Ziaminaria), while the more posterior dorsal fin rays, having short lateral branchlets, 

 counterfeit in a like manner the plant-like hydroid zoophytes known as S&rtularim. 

 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, repro- 

 ducing 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 irregular polygonal areas, whose 

 pattern is at once recognized by the student of marine zoology, as corresponding with 

 that of the flat, cushion-like expansions of the compound tunicate, Botryllus viola- 

 ceiis. Thus disguised at every point, the angler has merely to lie prone, as is its wont, 

 among the stones and debris at the bottom of the sea, and to wait for the advent of 

 its unsuspecting prey, which, approaching to browse from what it takes to be a flat 

 rock — differing in no respect from that off which it obtained the last appetizing 

 morsel of weed or worm — finds itself suddenly engulphed beyond recall within the ' 

 merciless jaws of this marine impostor." 



Half a dozen species of anglers have been described, the best known being the 

 one common to the northern parts of Europe and America, the LopMus piscatorius, 

 which is figured on page 177. 



