318 A. Crane—Classification of the Brachiopoda. 
VI.—New CLASSIFICATIONS OF THE BRACHIOPODA. 
By Acnzs Crane. 
R. CHARLES SCHUCHERT, of Newhaven, Conn., U.S.A., 
has recently published in the ‘‘ American Geologist” (Vol. xi. 
No. 8) an important and highly suggestive “Classification of the 
Brachiopoda,” based on the history of the class (Chronogenesis) and 
the ontogeny of the individual. It embodies the latest results of the 
remarkable investigations on the Palaeozoic forms of Prof. James 
Hall and Mr. J. M. Clarke, who have thrown so much light on the 
evolution of genera among the Brachiopoda in the eighth volume 
of “The Paleontology of New York” (Part I. Brachiopoda, 1892). 
Mr. Schuchert adopts the ordinal system proposed in 1891 by Dr. 
C. E. Beecher and thus divides the Cuvierian class Brachiopoda into 
the free and attached valves or sub-classes Lyopomata and Arthropo- 
mata of Owen, and the following sub-orders of Beecher, based on 
the nature of the pedicle passage and the stages of shell growth. 
(1) Atremata, with a free pedicle; (2) Neotremata, with pedicle 
opening in the ventral valve ; and (3) and (4) Protremata and Telotre- 
mata, their modified respective derivatives. Three out of these four 
sub-orders. were represented in the primordial fauna, and genera 
belonging to the fourth “ were in existence in the Trenton period of 
the Lower Silurian.” 
In 1877 one hundred and thirty! genera of Brachiopoda were 
recognised and divided by Dall into eighteen, and by Davidson, 
first into eleven,? and subsequently into fourteen family groups. 
Messrs. Hall and Clarke seemed inclined to abandon family designa- 
tions altogether and left the consideration of the matter for the 
second part of their work on the Paleeozoic genera (loc. cit.). Mean- 
while Mr. Schuchert has carefully performed a useful work in 
tabulating the enormous increase of genera recorded during the last 
sixteen years. They amount in all to rather more than twice the 
number, viz., two hundred and seventy-seven genera, which he 
classifies into forty-seven families, and proceeds to show that thirty- 
six out of these forty-seven were differentiated during the Paleozoic, 
that only nine survived in the Mesozoic, while six, or one-eighth of 
the whole number, are represented in the living faunas of existing 
oceans. 
Twenty-four genera are referred by Schuchert to the order 
Atremata, the oldest and simplest in structure, from which the 
Neotremata and Protremata almost simultaneously diverged. In 
the Telotremata, the most modern and numerous sub-order, he 
includes no less than one hundred and thirty-eight genera—the 
half of the whole—and considers these rostrated forms as all directly 
derived from the Neotremata. Paterina is regarded as the most 
primitive known genus of the order Atremata, which gave rise 
through the Trematidae to the Neotremata, while the Protremata 
1 «What is a Brachiopod?’’ Guox. Mac. June, 1877, Decade II. Vol. IV. 
2 General Summary of the ‘‘ British Fossil Brachiopoda,” Paleontographical 
Society, 1884. 
