dap 
‘ 
; Natural History of the United States, 213 
ity, according toa _— easily apprehended. The worm-like 
larve, a lower stage of an insect, attests that worms and crus- 
taceans are hier ts in grade toi nsects. And in eneral, a multi- 
plicity of seements and laxity of parts are proofs of inferiority : 
4s in close accordance, the T'rilobites, the earliest of Crustaceans 
ve an excessive multiplication of segments.* But to use the 
criterion of geological history with success, the principle already 
Stated, that the order of progress is on ly in a general way from 
the lower to the higher, that is, that the earliest are not always 
the very lowest, must be borne in min 
* Thi other of a 
tential and therefore more Sidipstesigk ee Fe wile ths melge has tthe 
trated in his U. S, Ex pl. E . Report on rustacea (chapter on Classification, p- 1395, 
and this Journal, xxii, 14), tis this pe cephalic elevation as to quality or grade 
Sarat with—and we ma Nea * et se growth it is Ered con- 
mal Kingdom. Com 
: paring grou be species ge 
deine mPrehensive form - The ts me 
in 
terior part 
toa dines head the lizard has fewer segment 
than > operate from the t thr Again, en ts te 
olGaghe firm] ie ese ar cranium ber the inferior quadruped: that is, san 
— ates ises. 
ieee aay explained appears to be a general one. But re hese espace: be- 
nue E a ~ usions onl n made among 
ht species or groups afford right com whole Ie is inferior in grade 
© same typical series; for when a 
ae © cannot of course pass from one ted wing § en- 
or d reover each type has its degradations (that is, species rep’ ting degraded 
to they wee te forms); and in this depauperai there is an abbreviation an 
one arising from the opposite principle, cephalization W tape-worm is 
of the lowest of species, ther rs still i which are better 
it rises jn ae nt of the tape-w While, again, the 
Btade, has its abd Ris tened till it becomes ‘ 
£0 at - lower end of per of Dew ene pods (the onthe pena aun that 
ina + Bat * gig which have a mvsiberlale 4 abdomen. e princi aes a 
iat e, arising of grade i is. anes ¢ rasp tration a 
With mane tiny > anda Fach pts 
Saber ; striae a ati iL engine. 
eriorly, and sometimes so sstectol \A 
oer 2 ay stem. It is pate gaa | to add that no ny pe rasa ‘into 
tioned. . is here implied, but that actual species aaceinak e conditions men- 
