Geology and Natural History. 157 
many Sipunculoids, as well as most of the Helminths (except in 
N . 
the “Vermes” from the rest of the Articulata, and calling the 
group a “sub-kingdom,” as some other writers 
n 
as 
structure, in some of their forms, that it has become a matter of 
extreme difficulty to find diagnostic characters for separating 
them, and few greater absurdities have been pro a : 
tion, in modern times, than to separate them in two “su ‘king- 
doms” or branches. On the same basis every class of animals 
ingdom.” 
Another feature of the arguments presented demands attention 
rom those who may wish to form an impartial judgment of them. 
The author naturally takes great pains in every case to point out 
all the resemblances between the organs of worms and those of 
Brachiopods that he compares, but he does not always allude to 
the Ra Thus, on p. 11, he compares the elongated 
