SKELETON OF VERTEIJRATA. 283 



tebratcd animals, however strong may be the contrast wliich 

 they offer in all the essential features of their conformation. 

 The rings whicli compose the skeleton of the insect, and 

 which enclose its principal nervous chords, have been sup- 

 posed to have an analogy with the circles of bone which con- 

 stitute the primary forms of the vertebrae, and which con- 

 lain the spinal chord; although, in the first case, it is true, 

 other viscera are included within the arches, whereas, none 

 are contained in the last case. They agree, also, in having 

 the head placed at one extremity, distinct from the trunk, 

 and containing the principal organs of the senses. Farther 

 correspondences have been likewise traced in the minuter 

 anatomy of these parts, which it would here occupy too 

 much space to examine in detail. 



An approximation is evidently made towards an internal 

 skeleton in the cephalopodous mollusca; wlicre we find a 

 central body, cartilaginous in some species, calcareous in 

 others. In the Loligo it has a long and slender shape, and 

 is pointed at the end like the blade of a sword; it bears, as 

 we shall hereafter notice, some resemblance to the cartila- 

 ginous spine of the fish called the Myxine, or Gasirobran- 

 chus, which does not enclose the spinal marrow, but only 

 admits it to pass along a groove in its upper edge. 



All these multiplied instances, when weighed together, 

 and united in a comprehesive view, are sufiicient to prove, 

 that there exist very perceptible links of connexion among 

 all the classes of created beings, even in those apparently 

 the most remote from one anotlier. They render it clear to 

 the discerning eye of the philosophic naturalist, that all tiie 

 races of animated beings are members of one family, and the 

 offspring of the same provident Parent, who has matured all 

 his plans on a deeply premeditated system, and who dis- 

 penses all his gifts with the most salutary regard to the ge- 

 neral welfare of his creatures. 



