134 Scientific Intedligence. 
appear from the following remarks: “ We find that in the Mollusks not 
only are the organs arranged upon the two sides of the body, but the 
‘weight of organization,’ as Prof. Agassiz expresses it, is thrown upon 
the sides, which even in common usage we recognize to have superior 
Eve these vie ® acta tke “ nature nothing could be more 
superficial than such characters. But in fact we place and examin 
various kinds of shells in aay different positions,—the Brachiopoda 
dorsally or ventrally, the Gasteropods sometimes dorsally, sometimes an- 
nest and posteriorly, sometimes inset meeting to their outward 
The natural positions are, also, equally variable, the bivalve 
sides. In Brachiopods the ventral valve appears to be uppermost, accord- 
ing to the homologies of Mr. Morse, while in Tunicates the sides are not 
his gain; “We no more think of placing or viewing an insect on 
ts side than a bivalve upon its upper or lower edge, which correspond to 
tine tergal and ventral regions of the Articulate. This seems rs confirm 
the idea that the single ring representing az Articulate unit is 
of an equal number “of segments above a elow a horizontal "biseetialg 
its edeaile to determine whether this type, vie cn defined outlines © 
so clearly illustrate the law, has at the same time the unsatisfactory in- 
xi arra’ newest it is certain that in our preeoit state of knowledge 
o 
the same principle in the other in a marked degree, especially 
use of this 
gions seen no where else among athutule The true explanation of 
these relations seems to be that all these various characters whether later- 
ality, tergality, symmetry or cephality, are most vee exemplified in the 
Vertebrate structure, while they exist to Bea or less extent 
gs 
lower animals, whether Articulates or Mollusks, ua path disappear OF 
are eee lost sight of in = lower Radiates, owing to the pre reponder 
ance of the radiate characte 
The Beptiey of stare Does symmetry or ; apes “e 
the author more specially considers, seems to be characteristic 
tebrates, and has not been observed among other animals. 
