398 Illustrations of Nature. 



perhaps, by the struthiones, approach the beasts, as they, by 

 the monotremata, again approach the birds, especially the 

 penguinese ; the penguins, scarcely able to walk, are allied to 

 the reptiles, as some of the chelonia to birds. Of the bran- 

 chiata or gill-breathers, the fish, which are vertebrated animals, 

 more or less developed, from soft membrane or cartilage with 

 horny integuments to more advanced, though far from perfect 

 bone, show their connexion with the other vertebrata by their 

 location in that part of the circle, where the aquatic pulmonata 

 approach them ; they are, in fact, in immediate contiguity 

 with the icthyoid reptiles of Blainville ; and the ophiognathus 

 of Harwood is a good instance of this connexion ; still they are 

 sufficiently distinguished both by their respiratory and circu- 

 lating systems. The Crustacea, which were part of the Linnaean 

 insects, but from which, by having branchiae, they are distinct, 

 show their alliance by being placed in that part of the circle 

 where the insects of the spiraculata intersect them. Many 

 other secondary alliances might be pointed out, such as the 

 approach of the chelonian reptiles, in which the skeleton is be- 

 coming external to the Crustacea, and these to the coleopterous 

 insects ; the connexion of the marsupialia, which belong to the 

 different tribes, in the same manner as the icthyoid reptiles 

 with the fish, &c., the development of the system will furnish 

 them, at every stage ; the accomplished zoologist will readily 

 pursue the plan ; but I am forbidden to dilate : perhaps, even 

 now, the limits of an outline have been exceeded ; and me- 

 thinks I hear some considerate friend suggest *' cui bono ?" a 

 cold unsympathising note of interrogation, which hath often 

 paralysed the efforts of the most ardent theorist. As a theorist, 

 permit me to explain ; for as it is an imputation I may have 

 incurred, I will own that it is a character of which I should be 

 proud, were the signification restrained to the original, the 

 proper meaning. For ©2a;§eft; signifies to behold, to contem- 

 plate ; ©£a;§Jo: should be translated, a contemplation ; and 

 ©£a;§£rtJtos-, contemplative. Hence, a theory is a contempla- 

 tion, or enlarged and liberal view; to theorise is to contem- 

 plate, i. e., to behold many subordinate particulars with refer- 

 ence to their mutual interdependence as parts of some greater 

 whole ; and, therefore, ©gcygor, a theorist, is a philosopher, in 



