i42 THE POPULAR SCIENCE MONTHLY 



THE PALEONTOLOGIC EECOED. Ill 



ANATOMY AND PHYSIOLOGY IN" INVERTEBRATE EX- 

 TINCT ORGANISMS 



By RUDOLF RUEDEMANN 



STATE MUSEUM, ALBANY, N. Y. 



THE inquiry into the position of anatomy and physiology in in- 

 vertebrate paleontology seems very appropriate at present, since 

 paleontology is steadily becoming more closely affiliated to zoology, and 

 the sphere of zoology is at present dominated by comparative anatomy 

 and physiology. 



Since, however, invertebrate paleontology has only the hard parts, 

 mostly outer shells, at its disposal, the view still prevailing among 

 zoologists that little is to be expected from it in regard to the solution 

 of the problems of anatomy and physiology of the lower animals seems 

 natural. Nevertheless, the results already attained prove that if paleon- 

 tologists do not ajDproach their material with a geological knowledge 

 only, as has been done in the past altogether too often, most gratifying 

 results may be obtained, at least in some classes, for it must be con- 

 ceded that the connection of the hard parts with the fleshy parts is very 

 unlike in different classes; it is very intimate in some, as the crinoids 

 and brachiopods, and again more indifferent, as in the gastropods. 



But it is not claiming too much for invertebrate paleontology if we 

 say that where the hard parts are of great structural importance, 

 paleontology has earlier taken cognizance of this fact and consequently 

 gone ahead of zoology. As an instance I may cite Zittel's investigations 

 of the skeleton of the hexactinellid sponges which have taught the 

 fundamental imjjortance of the form of the spicules and the structure 

 of the skeleton in that class and whose results have been readily 

 adopted by zoologists. In classes which, as the brachiopods and crinoids, 

 are to-day mere shadows of their former greatness, paleontology has its 

 greatest chance, and it would fail in its task if it would there not be- 

 come the instructor of the affiliated science; and it is gratifying to see 

 that this fact is finding recognition, as, for instance, in Ray Lankester's 

 " Treatise of Zoology," where the chapter on the crinoids has been 

 entrusted to Bather, a paleontologist and one of the best authorities on 

 crinoids. 



It is apparent that in such classes as those just mentioned, of which 

 only the last ends of the branches are still alive, the origin and nature 



