ANIMALS OF THE WHARF PILES 



THE NEW VINEYARD HAVEN GROUP 1 AS AN ILLUSTRATION OF 

 CERTAIN PHASES OF EVOLUTION 



By Roy W. Miner 



THE animal life which grows on the wharf piles furnishes a striking 

 illustration of one of the important adaptive phases of the process 

 of evolution — namely, specialization to an inactive life. In the 

 new Vineyard Haven wharf-pile group, recently completed for one of the 

 windows of the Darwin hall, an attempt has been made to emphasize this 

 principle, as well as to depict the abundance and beauty of the animals 

 themselves in their natural environment. The group illustrates a balanced 

 association in which the struggle for existence between animals is not 

 apparent, the majority of the species being plantlike and either incapable 

 of locomotion in the adult stage, or in possession of it to a very limited degree. 

 On the broken pile in the center of the foreground, for example, growing 

 over the mussels which have completely covered its stump are hundreds of 

 delicate pink hydroids (Tubularia crocea) clustered in feathery colonies. 

 Here and there among them peep forth the transparent solitary polyps of 

 the white-armed sea anemone (Sagartia leucolena), while the larger brown 

 sea-anemone (Metridium marginatum) expands its fringe-crowned disks on 

 this and the neighboring piles, interspersed with coral red masses of the 

 red-beard sponge (Microciona pro! if era). Although these flower-like forms 

 are relatively stationary and inactive, underneath their apparent peaceful- 

 ness and beauty the struggle for existence goes on as relentlessly as among 

 fierce free-swimming species, but with this difference, that their prey is 

 invisible to our eyes. The w r aters in which they are immersed are swarming 

 with myriads of microscopic creatures, while every polyp, with open rapa- 

 cious mouth and extended stinging tentacles is but a trap to entangle and 

 engulf them, and every sponge-colony with its million pores sucks in the 

 nutritious draft of organisms which are the ultimate basis of food for all 

 sea-life. In a word, sponges and polyps in spite of their size and wide 

 diversity of form are but little above the simplest of all animals, the one- 

 celled protozoa, and have developed as typically digestive organisms. 

 Since their food is everywhere present, organs of locomotion are not needed 

 to obtain it. Special senses and directive intelligence or instincts have n6t 

 been definitely evolved, since the evolution of these powers always goes 

 hand in hand with that of locomotor organs. It is true that certain polyps 

 possess somewhat aimless and imperfect methods of locomotion such as the 



i The field work, composition and effects for this group are the work of the author. The 

 modeling and preparation was done by Mr. I. Matausch assisted by Mr. E. Muller, the glass- 

 work by Mr. H. Muller, and the coloring by Messrs. S. Shimotori and I. Matausch, under 

 the supervision of the author. Through the courtesy of the United States Fish Commis- 

 sion the laboratories and equipment of its Woods Hole station were put at the disposal of 

 the Museum for the field work of this group 



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