90 LAY SERMONS, ESSAYS, AND REVIEWS. [vi. 



reveals, are bound together by an all-pervading unity of 

 organization, of the same character, though not equal in 

 degree, to that which enables us to discern one and the same 

 plan amidst the twenty different segments of a lobster s body. 

 Truly it has been said, that to a clear eye the smallest fact 

 is a window through which the Infinite may be seen. 



Turning from these purely morphological considerations, let 

 us now examine into the manner in which the attentive study 

 of the lobster impels us into other lines of research. 



Lobsters are found in all the European seas ; but on the 

 opposite shores of the Atlantic and in the seas of the southern 

 hemisphere they do not exist. They are, however, repre 

 sented in these regions by very closely allied, but distinct 

 forms the Homarus Americans and the Homarus Capensis: 

 so that we may say that the European has one species of 

 Homarus ; the American, another ; the African, another ; and 

 thus the remarkable facts of geographical distribution begin 

 to dawn upon us. 



Again, if we examine the contents of the earth s crust, 

 we shall find in the latter of those deposits, which have 

 served as the great burying grounds of past ages, number 

 less lobster-like animals, but none so similar to our living 

 lobster as to make zoologists sure that they belonged even to 

 the same genus. If we go still further back in time, we 

 discover, in the oldest rocks of all, the remains of animals, 

 constructed on the same general plan as the lobster, and 

 belonging to the same great group of Crustacea ; but for 

 the most part totally different from the lobster, and indeed 

 from any other living form of crustacean ; and thus we 

 gain a notion of that successive change of the animal 

 population of the globe, in past ages, which is the most 

 striking fact revealed by geology. 



Consider, now, where our inquiries have led us. We studied 

 our type morphologically, when we determined its anatomy and 

 its development, and when comparing it, in these respects, with 

 other animals, we made out its place in a system of classification. 



