8 PROCEEDINGS OF THE CANADIAN INSTITUTE. 



pods. The brachiopod is a bivalve, but with valves of unequal size. In the over- 

 whelming majority of cases in the fossil form the valves are found united, and, as 

 the valves are filled either with sediment or with crystallized matter, the interior 

 is rarely visible. This involved a greater difficulty than that of merely ascertaining 

 the marks of the attachments of the organs on the inner sides of the shells. The 

 brachiopods have supports for the soft parts, the so-called arms, in the shape of 

 loops or spirals, or other processes, and while in modern brachiopods these are 

 not calcareous, in fossil forms they were. These spiral and other processes were 

 occasionally but rarely exposed and separated valves showing the muscular markings 

 were also found, but naturally the first attempts at systematizing the brachiopods 

 were largely based on mere external characters. During the progress of Dr. 

 Davidson's labours, however, the Rev. Norman Glass, assisted him materially. 

 By the exercise of great ingenuity and delicate workmanship he removed the 

 shells and exposed the delicate brachial supports referred to, in the case of many 

 species, so that a greatly improved system was the result. It is but right to say 

 that others were working upon the brachiopods in the same direction, notably Mr. 

 Whitfield, of the American Museum of Natural History, New York. The number 

 of known fossil species has, however, kept on increasing at a surprising rate, and 

 we have also added largely to the known living forms. Dr. Davidson's work was, 

 therefore, soon followed by important contributions from D. P. Oehlert, in 1887, 'i-* 

 and by Professor Zittel in his Hand-book, already referred to. It was still main- 

 tained that we possessed no treatise in which "facts in regard to structure, function, 

 habits, and distribution of these animals, the distinguishing characters and sys- 

 tematic relations of their genera," are included in one work. This Professor Hall 

 and his co-workers have sought to do in the " Introduction to the Study of the 

 Brachiopoda " and in the eighth volume of the Paleontology of New York. Here 

 we can readily follow their history from the very minute and rudimentary brachio- 

 pods in the Lower Cambrian through their enormous development in thie Palaeo- 

 zoic both in numbers of individuals and in variety of form and size, continumg 

 in lessened though still great numibers through the Mesozoic, and gradually les- 

 sening until the present age, of which Professor Hall records only 147 species, 

 many of which are mere varietal forms. Whether we consider the shapes of the 

 ^'alves as they have been influenced by the soft parts which are now gone, the 

 microscopic structure of the shells, the systems of defence by spines, imitative 

 surface markings or otherwise, the infinitely varied and very beautiful processes 

 for supporting the arms, the muscular scars, the complicated nature of the hinge, 

 the foramen, the evidence as to fixity of habit or the reverse, or any other feature 

 wbidh may leave its morphological evidence on the fossil; or the softer parts 

 which may be seen in living forms and by the aid of which both the structure and 

 habits of the fossil organisms may at least to some extent be understood, we must 

 admit that the 'history of the Brachiopoda, as gathered from the study of both 

 fossil and living forms has produced a result infinitely more satisfactory to the 

 biologist and the geologist than could have been possible by the study of the 

 fossil forms alone by the old-fashioned geologist and of the living forms alone by 

 the old-fashioned biologist. And he would be a foolish man who undertook to 

 say whether the fossil or the living forms had most aided in the final result. Both 

 are absolutely necessary. 



In almost any other branch .of fossil remains quite as valuable evidence ol 

 the growth of palfeontoiogy on its biological side might be adduced. In the Pro- 

 tozoans, George Jennings Hinde by his microscopic work is carrying the evidence 

 of the existence of Radiolarian remains farther and farther back in the Palaeozoic 

 rocks, and Messrs. W. D. and G. F. Matthew have found Globigerinidae in pho? 



(i) Paul Fischer. Manuel de Conchyliologie, Paris, 1887, with an appendix on the Brachipods by D. P. 

 Oehlert. 



