ANIMAL LIFE. 51 ^ 



peculiarly spotted form common to the Mediterranean and adjacent 

 seas capable of liberating a charge that will shock man and must be 

 destructive to hosts of smaller animals, upon which it is doubtless used 

 as a means of offense and defense; in the electric siluroid of Africa, 

 which in different structure possesses the same power in greater force, 

 and still more pronouncedly in the electric eel of South America, the 

 shock from which is sufficient to paralyze a horse. What strange com- 

 bination of circumstances has conspired to develop such a power in 

 these animals? Evidently some condition common to their several 

 environments, as it must have originated independently in each of the 

 examples cited. The difference in position and structure, though all 

 are modified from muscular tissue, is such that no common origin can 

 be assigned to the structure in the different forms. 



In the adaptations to deep sea life we have one of the greatest 

 extremes and, since we have here one of the most remarkable series of 

 animals and moreover one which until recent years has been unknown 

 to science, it will not be amiss to give it more than passing notice. In 

 the greater depths of the ocean we have conditions rivaling those of 

 caves in the absolute exclusion of light, but very different in the 

 medium and in the enormous pressures to which the animals are here 

 subjected — pressures so great that when deep sea animals are brought 

 TO the surface there is an expansion of all the soft parts, an extrusion 

 of the eyes, stomach, etc., producing most monstrous looking forms. 

 But the passage from moderate depths to deeper and deeper points and, 

 finally, to the abysses of mid-ocean are gradual, and we can conceive 

 a gradual pushing off to deeper and deeper points till enormous depths 

 are reached. Even yet, however, it is believed that the deepest reaches 

 are uninhabited and uninhabitable, the lowest points from which life 

 forms have been secured being far above the extreme depths that are 

 knovni. 



The wonderful discoveries of the 'Challenger,' 'Albatross,' 'Blake' 

 and other deep-sea explorations, adding a new chapter in science and 

 whole new groups of animals hitherto unsuspected, are yet so fresh in 

 the minds of those interested in such matters that they may well serve 

 my purpose in illustrating those special adaptations reached by animals 

 that have pushed into apparently inhospitable regions. The passage 

 in this case has, however, been slow. We need assume no sudden 

 change of physical conditions tending to produce modifications of struc- 

 ture, but practically unaltered physical conditions and a simply crowded 

 condition of life forms in regions already occupied, as the main factor 

 in pushing into this hinterland of habitable zones. Here as in caves 

 we should expect the loss of light to result in the loss of eyes, but this 

 is not always the case, for in some of these grotesque denizens of the 

 deep instead of the loss of eyes we find the development of marvelous 



