13 
has arranged it. But it seems that he has confounded Stri- 
gocephalus and Uncites of Defrance with Pentamerus, from 
which they are really distinct, and placed Gypidia (to which 
genus Goldfuss has referred Uncites Gryphus of Defrance) 
under Delthyris, along with Spirifer and Orthis. If the 
principles of Von Buch’s arrangement of the Brachiopods 
are to be adopted, it will be necessary to place many of the 
species of his genus Terebratula in the genus Delthyris, 
and subdivide that genus into Strigocephalus, Pentame- 
rus, Atrypa, Spirifer and Orthis. Calceola and Thecidea 
would come well before Strigocephalus ; and Leptaena (in 
the structure and use of whose tubular spines he has been 
misled) will follow Orthis. So the section “ Ohne Perfora- 
tion ” (without any perforation at the edge of the hinge) 
will be found unnecessary, and Terebratula and Magas 
will stand together ; this arrangement will be found very 
natural. 
I would propose the following distribution of the order 
Brachiopoda, as an improvement upon that of Von Buch. 
Brachiopoda. 
~Hinge none. 
Lingula. 
Animal attached to fo- 
reign bodies by the edge 
of the shell through the 
medium of a membranous 
tube and ligamentous fi- 
-bres. 
With a hinge. Aperture" 
for the fibres of attachment Terebratula. 
confined to the beak of the Magas. 
larger valve. 
With a hinge. Aperture 
for the fibres between the • 
valves. 
Calceola. 
Thecidea. 
Strigocephalus. 
Pentamerus. 
Atrypa. 
Spirifer. 
Orthis. 
Leptajna. 
Animal attached by fi- 
bres penetrating the disc 
of one valve. 
1 
Orbicula. 
Animal attached by the 
surface of one valve di- 
rectly. 
Crania. 
