Sect. XXXIX. 4. 8. GENERATION. 397 



of foot, as the hare. Others have acquired hard or armed fhells* 

 as the tortoiie and the echinus marinus. 



Mr. Ofbeck, a pupil of Linnaeus, mentions the American 

 frog-fifh, lophius hiftrio, which inhabits the large floating iflands 

 of fea-weed about the Cape of Good Hope, and has iulcra re- 

 icmbling leaves, that the fifhes of prey may miftake it for the 

 fea-weed, which it inhabits. Voyage to China, p. 113. 



The contrivances for the purpofes of fecurity extend even to 

 vegetables, as is feen in the wonderful and various means of 

 their concealing or defending their honey from infects, and their 

 feeds from birds. On the other hand fwiftnefs of wing has 

 been acquired by hawks and fwailows to purfue their prey ; and 

 a probofcis of admirable ftructure has been acquired by the bee, 

 the moth, and the humming bird, for the purpofe of plundering 

 the nectaries of flowers. All which feem to have been formed 

 by the original living filament, excited into action by the hecef- 

 fities of the creatures, which pofTefs them, and on which their 

 exiftence depends. 



From thus meditating on the great fimilarity of the ftructure 

 of the warm-blooded animals, and at the fame time of the great 

 changes they undergo both before and after their nativity ; and 

 by considering in how minute a portion of time many of the 

 changes of animals above defcribed have been produced ; would 

 it be too bold to imagine, that in the great length of time, fince 

 the earth began to exift, perhaps millions of ages before the 

 commencement of the. hiftorv of mankind, would it be loo bold 

 to imagine, that all warm-blooded animals have arifen from one 

 living filament, which the great First Cause endued with an- 

 imality,with the power of acquiring new parts attended with new 

 propenfities, directed by irritations, fenfations, volitions, and aflb- 

 ciations ; and thus pofiefTing the faculty of continuing to improve 

 by its own inherent activity, and of delivering down thofe im- 

 provements by generation to its poflerity, world without end ? 



Sixthly, The cold-blooded animals, as the fifh-tribes, which 

 are furnifhed with but one ventricle of the heart, and with gills 

 inftead of lungs, and with fins inftead of feet or wings, bear a 

 great fimilarity to each other ; but they differ, neverthelefs, fo 

 much in their general ftructure from the warm-blooded animals, 

 that it may not feem probable at firft view, that the fame living 

 filament could have given origin to this kingdom of animals, as 

 to the former. Yet are there fome creatures, which unite or 

 partake of both thefe orders of animation, as the whales and 

 icals ; and more particularly the frog, who changes from an 

 aquatic animal furnifhed with gills to an aerial one furnifhed 

 I with lungs. 



The 



