520 Reviews—J. Hall & J. M. Clarke— Paleozoic Brachiopoda. 
Messrs. Hall and Clarke consider, however, the latter as probably 
congeneric with Quenstedt’s genus Mentzelia (Spirifer medianus), 
from the Silesian Muschelkalk. They hold them to be connected 
with the post-Paleeozoic members of the genus Spiriferina from the 
presence of the median septum, and associated with the glabrate 
Spirifer on account of the punctation of the epidermal layer of the 
shell: This classification of the American species of Spirifer is 
presented in a convenient tabular form, with time limits of species 
indicated, and will stand examination better when it can be com- 
pared with the plates destined to illustrate the volume. 
Dalman’s genus ?Cyrtia and Davidson’s Cyrtina are retained. 
The latter comprises the first indication of shell puncture among 
the Spiriferoids. Winchell’s genus, Syringothyris, is considered as 
defining species ‘‘outcome from Spirifer along the line of the 
Ostiolati,’” while D‘Orbigny’s Spiriferina covers species with 
characters derived from the lamellose-septate Spirifers dating from 
Upper Silurian times. The genus Ambocelia, Hall, is a small 
spire-bearing Devonian type, and his new genus Metaplasia is 
proposed for a little shell originally described as Spirifer pyxidatus, 
but not yet proved to be a spire-bearer, while its external form 
recalls that of Orthis. It is somewhat allied to Spirifer cheiroptyx, 
D‘Arch. and De V., from Paffrath, and to S. Oceani, D‘Orb., from 
the Carboniferous limestone of Visé, and for this aberrant group 
Hall and Clarke suggest the designation Verneuilia. The term 
Whitfieldella is proposed for certain forms of Meristoids, of which 
Atrypa nitida, Hall, is taken as the type, hitherto described as 
Meristina, that generic name being now restricted “to species similar 
to M. Maria, Hall, which these authorities do not consider to be 
specifically identical with Atrypa tumida, the tpye of Davidson’s 
non-acceptable genus Whitfieldia, a synonym of Meristina. 
In all, Hall and Clarke now recognise forty-eight genera of 
Paleozoic spire-bearing Brachiopoda, of which twelve new genera 
and subgenera are now described and figured by the authors for 
the first time. Twelve others have been admitted as valid by 
various authors since Davidson’s Summary and Appendix was 
published in 1884. The claims of a few others, such as King’s 
genus Cliothyris, type Athyris pectinifera, Aclinoconchus, M‘Coy, 
(Athyris planosulcata) and Seminula, M‘Coy (4. ambigua), are re- 
admitted, and the balance remain much as Davidson defined them, 
with the exception of his genus Bifida, which the American paleon- 
tologists regard as synonymous with Anoplotheca, Sandberger, and 
Anazyga, Dav., based on Atrypa recurvirostra, which is merged in 
Zygospira, type Producta modesta, Say. The divergent position of 
the loop is shown to be a matter of individual variation, of which 
Zygospira modesta and Z. recurvirostra (Anazyga) represent “extreme 
possibilities of variation.” Winchell and Schuchert’s supposed 
primitive terebratuloid genus Hallina is also referred to Zygospira, 
which seems to be represented by numerous species in the ‘Trenton, 
Hudson River group and Niagara shales of America. 
We subjoin a list of the new genera proposed by Hall and Clarke. 
with the types on which they are founded. 
os 
