Reviews—J. Hall & J. M. Clarke—Paleozoie Brachiopoda. 519 
species of India had also been well described and illustrated by 
Waagen, and the post- Paleozoic genera, comparatively few in number, 
by Bittner and other authorities. So that ample material awaited 
the New York paleontologists, who have now given us a complete 
survey of this interesting group of fossil Brachiopoda, with special 
reference to the American species. 
The authors commence with the variable and numerous species 
of the genus Spirifer, of which they concur in recognizing Martin’s 
Anomites striatus as the type. About two hundred American 
Palaeozoic species are recorded and subjected to careful comparison 
and revision. They are held to be all congeneric, and the species 
are therefore (not for the first time in the history of the genus) 
classed in groups in accordance with the manifold external variations 
and salient features of an ornamental character. 
This method of comparison leads the authors to formulate the 
novel and highly suggestive conclusion “that these external differences 
make an excellent basis for a grouping of the members of this protean 
genus, and one not merely conventional and arbitrary, since it serves 
to indicate, within the integrity of the genus, lines of progress leading 
to resultants which are no longer congeneric” (p. 11). 
We summarise the classification they propose of six main groups 
of species, viz. : 
I. Rapratt. A primitive type with few, many, or double pli- 
cations, of which S. radiatus, including S. plicatellus, Sby., 
are held to be typical examples. 
IJ. Lamennost. a. Septati, with a median septum in the pedicle 
valve. SS. permallosus, Hall, is given as a typical example. 
b. Aseptati, without median septum, S. mucronatus, Conrad, and 
S. sub-mucronatus, Hall. 
Ill. Fimsriatit. a. Unicispini=Delthyris, Dalman, sensu stricto, with 
short, simple, hollow spines, such as S. crispus, Hisinger. 
b. Duplicispinei = Reticularia, M‘Coy, with large compound 
‘ spines, often with lateral branches, of which S. fimbriatus, 
Conrad, is the earliest example from the Hamilton group, 
S. lineatus, Martin, a well-known Carboniferous form. 
IV. Apgrruratr. Forms with plications on the sinus fold and 
sinus, of which S. aperturatus, Schlotheim, S. disjunctus, Sby., 
and S. striatus, Martin, are cited as typical examples. 
VY. Osrionatr. Median fold and sinus without plication, such as 
S. ostiolatus, Schlotheim, S. Oweni, Hall. These are the 
syringothyroid spirifers. 
VI. Guasrart. Smooth shelled species sub-divided into: 
a. Aseptati= Martinia, M‘Coy, type S. glabra, rare in America. 
B. SEPTATI, with dental plates or septa well developed, again 
subdivided into : 
1. Martinopsis, Waagen’s genus, for species with lamellee in both 
valves, from the Productus limestone of India. 
2. Tschernyschew, type Martinia semiplana, Waagen, for shells 
with a prominent median septum in the pedicle valve and 
dental lamellz scarcely developed. 
