15 



exhiljiting characters which sejjarate it from all birds known 

 hitherto, it having a long vertebrate tail, and apparently other 

 characters equally exceptional, but which are not at present 

 capable of being defined with accuracy, from the imperfect srate 

 of tlie remains of the only specimen hitherto examined. 



The above remarks are in reference to the vertebrate division 

 of animals ; but they apply equally to the invertebrate, the several 

 classes of which seem in like manner to be all connected by 

 osculant forms, while there is a genus of fishes, — the Am})hioxiis 

 of Yarrel found on our own shores, — so low in its organisation, 

 and with the vertebral column so imperfectly developed, as to 

 present more the appearance of a moUusk than a fish, and actually 

 to have been 'classed with the moUusca by one naturalist (the 

 celebrated Pallas) ; thus showing that even the two great divisions 

 of Vertebrata and Invertebrata have no such clearly defined 

 boundary between them as might have been supposed.* We 

 know yet further the bold hypothesis of one of the most philo- 

 sophical naturalists of our day, — not entirely unsupported by 

 facts, nay, with a large body of fccts in its favour, though 

 certainly not proved, nor capable of being proved, — that all the 

 different forms of mineral and vegetable life may have sprung 

 originally from at most but a vevy few 2>rimitive germs, which, 

 hy continued development under constantly altering conditions of 

 life through a long succession of ages, have given rise to all the 

 different species and varieties we see at the present day, whether 

 in the fossil or living state. Into these speculations Ave will not 

 enter. I only mention them in connection Avith Avhat I j^reviously 

 stated, — to shoAV hoAv necessary it is for the student of any par- 

 ticular department of Natural History to be acquainted in a 

 general way with all the other departments. Whether the several 

 species of animals and plants have had an independent origin or 



* The above remark applies to outward form alone, for there is no d'ubt 

 as to the Amphioxm, iu internal structure, beiug a true Yei-tebrate. 



