BRACHIOPODA. 
5 
In 1836 M. Deshayes {Lamk. Hist. Nat. Anim. sans Vert. vii. 
309) proposed the following arrangement : — 
Brachiopodes. 
I. Valves articulees. — 1. Productes, Produetus. 2. Terebra- 
tules, Terebratule. 3. Thecidees, Thecidee. 
II. Valves libres. — 4. Lingules, Lingule. 5. Orbiculees, Or- 
bicule. 6. Cranies, Calceola, Cranie. 
Dr. Gray in 1840 {Synopsis Brit. Mus. 1840, i. f. 7) divided 
the order thus 
The family of Terebratulidee are regular, and somewhat like a 
Grecian lamp in form, and have therefore been called Lamp- 
shells. The valves are articulated together, and are attached by 
means of a tendinous band, which passes out of the hole in the 
apex of the upper valve as in Terehratula and Spirifer. 
The Lingulida are attached by a tendinous tube, resembling 
the stem of the Barnacles, which projects between the apices of 
the gaping valves. 
The Discinidw, on the other hand, have the tendon passing 
out of a linear slit near the middle of the under valve. 
And at p. 155 gives a list of the genera as follows ; — 
1. Lingulidce, Lingula. 2. Terebratulidce, Terehratula, Spi- 
rifer. 3. Productidce, Produetus, Calceola. 4. Thecideidee, 
Thecidea. 5. Craniadm, Crania. 6. Discinidee, Discina. 
In 1841 Mr. John Phillips {Figures and Descriptions of the 
Paleeozoic Fossils, 8vo, p. 54) arranged the genera of Brachiopoda 
thus : — 
1. Valve free, attachment by exserted muscle. 
A. Valves equal. 1. Lingula. 
B. Valves unequal. 
a. Larger valves imperforate, Athyridce; * no cardinal area, 
Producta ; ** a cardinal area, Calceola. 
b. Larger valve perforated in or under the beak. 
Perforation reaching to the hinge-line, Delthyrida. 
Cardinal area more or less common to both valves, Orthis. 
Cardinal area confined to the large valve. * Internal plate of the 
larger valves separate, Spirifera. ** Internal plates of the larger 
valve united on the inside line of the shell, t Plate narrow, 
Strigocephalus. ft Plates very narrow, Pentamerus. 
Cardinal area obsolete, beak incm-ved over a minute perfora- 
tion, which is often obtect, or merely serves to receive the beak 
of the smaller valve, Cleiothyris. 
Perforation not reaching to the hinge-line, Cyclothyridce. 
* Beak truncate, perforate, Epithyris. ** Beak acute, the per- 
foration below it, Hypothyris. 
