102 LAY SERMONS, ADDRESSES, AND REVIEWS. [vr» 



fish, the rock lobster, and the prawn, and the shrimp, for 

 example, however different, are yet so like lobsters, that 

 a child would group them as of the lobster kind, in con- 

 tradistinction to snails and slugs : and these last again 

 would form a kind by themselves, in contradistinction to 

 cows, horses, and sheep, the cattle kind. 



But this spontaneous grouping into " kinds" is the 

 first essay of the human mind at classification, or the 

 calling by a common name of those things that are 

 alike, and the arranging them in such a manner as best 

 to suggest the sum of their likenesses and unlikenesses 

 to other things. 



Those kinds which include no other subdivisions than 

 the sexes, or various breeds, are called, in technical 

 language, species. The English lobster is a species, 

 our cray fish is another, our prawn is another. In other 

 countries, however, there are lobsters, cray fish, and 

 prawns, very like ours, and yet presenting sufficient 

 differences to deserve distinction. Naturalists, therefore, 

 express this resemblance and this diversity by grouping 

 them as distinct species of the same " genus." But the 

 lobster and the cray-fish, though belonging to distinct 

 genera, have many features in common, and hence are 

 grouped together in an assemblage which is called a 

 family. More distant resemblances connect the lobster 

 with the prawn and the crab, which are expressed by 

 putting all these into the same order. Again, more 

 remote, but still very deifinite, resemblnaces unite the 

 lobster with the woodlouse, the king crab, the water- 

 flea, and the barnacle, and separate them from all other 

 animals ; whence they collectively constitute the larger 

 group, or class, Crustacea. But the Crustacea exhibit 

 many peculiar features in common with insects, spiders, 

 and centipedes, so that these are grouped into the still 

 larger assemblage or " province " Arliculata ; and, finally, 



