17 



ages, as if they formed a chain in evolution, but it will separate, 

 link after link, in like mariner, under the glance of a scientist. 



A knowledge of evolution followed the domestication of animals 

 centuries ago but how and where it takes place is a subject of mod- 

 ern investigation. And we do not know how or where it has taken 

 place, except as a result of observation and experiment. The theory^ 

 of evolution does not account for anything, though an established 

 fact may be consistent with the theory. All biological knowledge 

 follows the discovery of the hard and soft parts of the anatomy of 

 living animals, but among extinct fossil animals it is only to be in- 

 ferred after a full knowledge of the hard parts found preserved. 

 And Agaricocrinus is a good genus with which to make an illustra- 

 tion. We know that some crinoids, as Encalyptocrinus, were per- 

 manently attached by roots that penetrate the mud, at the bed of 

 the sea, like a forest tree penetrates the soil on land, that others, 

 like Anomalocrinus attached roots to foreign objects, or were free, 

 like Pycnocri?ius, and though floaters could attach themselves by 

 coiling the tapering ends of their columns around other objects; but 

 we do not know to which of these divisions Agaricocrinus belonged. 

 We know that the columns in some crinoids were square, others 

 pentagonal and others round and that the column of Agaricocrinus 

 was round; but we do not know what significance, if any, in the line 

 of development, is to be attached to the form of the column, its 

 structure, or the shape of the columnar canal. We know nothing 

 of the internal anatomy of the calyx or head of Agaricocrinus and 

 cannot trace the source of the genus, if it is to be found, in known 

 species of earlier age or find the evidences of its survival, if it did 

 survive, in later crinoidal forms. 



We know by the three basals, absence of subradials, presence of 

 primary radials and regular interradials, that Agaricocrinus must be 

 classed, in the family Actinocrinidoz, which is established on the 

 hard parts of the fossilized tests, and which has had no representa- 

 tive, so far as discoveries have progressed, since the Subcarbonifer- 

 ous age. They ante-date the Carboniferous period. An old Eng- 

 lish naturalist said, ' 'Providence maintains and continues every 

 created species; and we have as much assurance, that no races of ani- 

 mals will any more cease, while the earth remaineth, than seed time and 

 harvest, cold and heat, summer and winter, day and night." But 

 we have, on the contrary, every assurance that observation, discov- 

 —3 



