14 



hingeless Neotreraafca and articulated Protremata from the 

 ancestral stock of hingeless Atremata with free pedicle passage 

 through both valves. This order contains 24 genera, of which 

 22 were envolved during palaaozoic time, and onlj two persisted 

 through all the geological ages and still survive. Of the 31 

 genera of derived hingeless Neotremata, three are found in 

 recent oceans, but out of 82 genei*a of articulated Protremata 

 one only was spared to us, the little Lacazella, a thecidoid of the 

 Mediterranean Sea. By far the larger number of living 

 forms belong to the order Telotremata,the last to be differentiated. 

 Its members had their rise in the Protremata, being envolved via 

 the Cambrian genus Kutorgina from Paterina, the little father o£ 

 all the Brachiopoda. 



It was largely to American scientists, Miss Crane stated, that 

 we owed the discovery of the radical stock of many of the 

 invertebrate classes. Such radical for the Brachiopoda was the 

 genus Paterina, a small inarticulated shell which passed through 

 no earlier stages of development and bears a close resemblance to 

 the first developed shell covering of both the larval brachiopod of 

 recent species and fossil forms of many branches. It was demon- 

 strated that many early fossil genera passed successively through 

 a " paterine " and an " obolleloid " stage before assuming the 

 " linguloid " shape, and that the larva or young of Terebraf ulina 

 passed through its linguloid stage before attaining mature tere- 

 bratuloid characters. Hence the individual or ontogenetic de- 

 velopment of a species confirms the phylogeny or ancestral history 

 of the race. The application of these important methods of 

 investigation we owe to Heckel of Jena, Hyatt of Boston, and 

 jBeecher and Clarke ; and to Clarke and Professor James Hall, 

 the philosophical contemporary of Davidson, we are indebted for 

 magnificent works on the development of Silurian forms and the 

 demonstration of the evolution of the palaeozoic Brachiopoda in 

 general. 



During the last twenty years the history of the class has 

 been completely re-written, and the Brachiopoda now seem to 

 justify the prescience of Darwin. Formerly regarded as one of 

 the most obstinate diflficulties in the way of the demonstration of 

 the evolution of invertebrate life on earth, they now bid fair to 

 become a remarkable illustration in favour of it. It is no longer 

 possible to doubt that the life history of the class does yield con- 

 vincing testimony of the truth of the law of evolution ; and to the 

 establishment of this fact, American scientists have largely con- 

 tributed. Their work is the more creditable to them, because so 



