J. W. Dawson—Paleozoie Land Snails. 403 
Archaster Agassizii Verrill, sp. nov. 
A large and elegantly formed species, with rather large pen- 
tagonal disk and wide, rapidly tapered arms. Color, in life, 
bright orange-red. 
Luidia elegans ? Perrier. Arch, Zool. Expér., p. 256, 1876. 
The species taken by us grows to more than 350™ in 
diameter. Color deep orange above, lighter below. Paxille 
crowded, smallest in middle of arms; large laterally ; each 
a la roup of slender spinules, and usually one to 
three larger, blunt pedicellarie. Marginal plates with a vertical 
row of three long, tapering, acute spines, the upper ones largest ; 
adambulacral plates also with a row of three sharp spines, 
which are smaller and recurved; the middle one largest. A 
row of large, ovate, bilabiate pedicellarie between the lateral 
and adambulacral plates. The specimen described by Perrier 
was very young, if of this species. 
Art. XLII.—Revision of the Land Snails of the Paleozoic era, 
with Descriptions of New Species; by J. W. Dawson. 
THE Gasteropods as a class occur as early as the Upper Cam- 
brian, but all the earlier known types are marine. That por- 
tion of the group distinguished by the possession of air sacs 
instead of gills (Pulmonifera) has not hitherto been found in 
any formation older than the Carboniferous, and only four Car- 
boniferous species have been described. In the present paper 
