186 JULY. 



stalk, also furnished with whorls of filaments, which is 

 fixed by its base to the solid rock. 



Altogether, the series presents us with one of the 

 most instructive and most marvellous examples of the 

 vast variety of external form and internal structure 

 which may be assumed by almost insensible modifica- 

 tions of one plan of organization; and so of the un- 

 fathomable resources of wisdom in the ever-blessed 

 God. For every one of these links, and there are 

 multitudes which I have not named, found either in 

 remote seas or in a fossil condition, that fill up the gaps 

 with close gradations displays an essentially common 

 model ; and the least fragment of the stony skeleton of 

 any one would be sufficient to enable a competent 

 naturalist to decide authoritatively, the instant he 

 looked at it beneath his microscope, that it belonged 

 to the great class ECHINODERMATA. The calcareous shell 

 of which the framework is composed, a glass made of 

 lime, is deposited in a fashion which, while common 

 to all, is found nowhere else throughout the whole 

 animal kingdom. 



Let us turn from these investigations, fascinating as 

 they are, to examine the ways and means of two or three 

 other creatures, familiar enough to us who habitually 

 explore the sea-margin. I allude to certain members 

 of the great class CKUSTACEA, not Crabs nor Lobsters 



