152 NEW YORK STATE MUSEUM 



attached condition among organisms involves and expresses degen- 

 eration and necessarily promulgates still further decline, biologists 

 are well agreed/ An argument therefore to show that groups of 

 attached organisms like the corals, the sponges, the bryozoans, 

 are degenerate and that their apparent simplicity of structure is 

 less a primitive than a derived condition, is not here called for. 



As we contemplate the earliest faunas of the earth we find 

 that adherent and attached forms of life are in a notably less 

 proportion than in the faunas succeeding. Bryozoans, crinoids, 

 corals, sponges, attached worms are extremely rare; trilobites and 

 brachiopods enormously predominate. The trilobites were crawlers 

 and swimmers. The brachiopods however were of different habit. 

 The predominating forms were the inarticulate species allied in 

 structure to the living Lingula and, if allied also 4n habit, 

 burrowed in the mud of the sea bottom with their fleshy pedicles, 

 potentially not actually attached. Some of the genera with long 

 pedicle sheaths may not have had this habit but have been actually 

 attached to solid objects by their arm; this was undoubtedly the 

 habit of the articulate brachiopods also until the time came with 

 the maturity of these creatures when the arm was atrophied and 

 they fell back on the sea bottom, free but still incapable of loco- 

 motion. In this condition, like many bivalves (e. g. Mya, the soft- 

 shelled clam, which lies buried in the mud with no power- to get 

 any way but further in) they were potentially attached though 

 actually independent. 



To the faunas earlier than the Cambric with their probable 

 decrease of attached organisms, we can not appeal. We can, 

 however, still follow the line of our argument into those earlier faunas 

 which still remain unrevealed. 



In all shell bearing organisms the shell is not a primitive but a 

 secondary development. Primitive organisms, as all considera- 

 tions of biology insist, were shell-less throughout their existence — a 

 conclusion not only indicated b}'- ontogeny but by philosophy. The 

 generally accepted conception that the archetype of organic life was 

 a naked free-swimming pelagic creature may be supplemented by the 

 proposition that the primitive condition of all organisms even, after 

 departure from the radicle was still naked and free. We must con- 

 ceive that only as the independent soft -bodied animals of the earliest 



^See especially Arnold Lang. Einfluss der fests'tzenden Lebensweise. 



