ON BIOLOGY. 



cently made by Mr. Walcott of the United States Geo- 

 graphical Survey. 



Knowing as \ve do the fundamental morphological plan 

 of structure as it is variously exemplified among the 

 several orders of plants; the main groups of the inverte- 

 brata; and among the vertebrates; we can look for nothing 

 more among all the paheonlotoglcal material which will 

 assuredly be brought to light in the future than interest- 

 ing modifications of those several plans of structure. 

 Such discoveries in some instances, undoubtedly, will 

 bring before us some very remarkable facts, but they 

 will ever be in harmony with the facts already known to 

 us. The most we can look for in such directions is a 

 progressive refinement in our knowledge of the affinities 

 of existing organisms, and the affinities of i he various 

 species, genera, and families long since extinct. Light 

 will constantly also be thrown upon the morphological 

 enigmas as they now stand to us among many of the ex- 

 isting species of animals and plants. 



The fact I wish to distinctly impress however, is that 

 our knowledge of morphology, in general, is at present of 

 such a nature that it absolutely admits of our prophesy- 

 ing, from the known data of the anatomical character of 

 animals or plarts in our possession, what kind of forms 

 we will probably meet with among the yet undiscovered 

 fossil tjpes in the future. Such prophecies have in 

 several instances actually been made, and it is one of the 

 grandest triumphs of which humanity has to boast, that 

 in a number of cases those prophecies have actually been 

 fulfilled. For instance, the fundamental plan of the 

 hand and foot among all the higher types of vertebrates 

 is pentadactyle, or five digits upon either member. Now 

 when we discovered the fossil Orohippus in the line of the 

 ancestors of our modern horse, it was seen that it had but 

 four complete toes on the front limb and three toes upon 

 the hind limb. The prophesy was made, based upon our 

 knowledge of the fundamental plan of the foot and hand 

 in the group to which it belonged, that if we were ever so 

 fortuna'e as to meet with the ancestral form from which 

 Orohippus was derived it would approach still nearer the 

 pentadactyle type. A number of years afterward the 

 prophecy was most beautifully fulfilled by the discovery 

 of the fossil Eohippus, in the ancestral line of the horses, 

 which supplied the required conditions. 



Permit me to present you with one more instance of 

 this kind not the first one that has happened, nor, mark 

 my word, will it be the last one of a similar nature: The 



