THE 
AMERICAN GEOLOGIST 
Vol. XI. MARCH, 1893. No. 3 
A CLASSIFICATION OF THE BRACHIOPODA. 
By Charles Schuchert, New Haven. Conn. 
Plate Y. 
The class Bracliiopoda, since 1858, has been divided by nearly 
all systematists into two orders, based on the absence or pres- 
ence of articulating processes. These divisions were recognized 
by Deshayes as earl}' as 1835, but not until twentj'-three years 
later were the names Lyopomafa and ArfJirojwmata given them bj' 
Owen. These terms have been generalh' adopted by writers, 
though some prefer IiKirtlcnlatd and Articnlnfa of Huxle}', or 
'Bvonn's Eri I nil III s and Trstaiinlines. Bronn,''in 18G2, and King,'' 
in 1873, while retaining these divisions, considered the presence 
or absence of an anal opening more important than articulating 
processes, and accordingl}^ proposed the terms Phuropyijia and 
Ajiijyia, and Tn'tcntrrota and Clistiniterata, respectiveh'. Many 
paleozoic rostrate species of Clistehteratu, however, give evidence 
that an anal opening was also present, and, therefore, the absence 
or presence of this oi'gan is not so persistent a character as that 
of a hinge. 
Von Buch,' in 1834, also divided the class into two sections, 
founded on the mode of attachment. The first section contained 
all brachiopods fixed by a pedicle to foreign bodies, while the 
second is restricted to those forms in which there is no pedicle at 
maturity, the entire lower or ventnd valve l)eing cemented toother 
