BRACHIOPODA. 
31 
Thomas Davidson and William King,* and though fifteen years have now 
elapsed since the date of its publication, later observations have hitherto added 
comparatively very little to the results achieved by these eminent investigators, 
and have taken nothing away from their value. The scope of this work in¬ 
cluded not only a detailed discussion of the characters and relations of the 
family, involving the establishment of an elaborate anatomical nomenclature, 
but also descriptions of all the species then known to represent the three genera, 
Trimerella, Monomerella and Dinobolus. This nomenclature we have adopted 
without essential modification, and its application is sufficiently explained by 
the accompanying 
outlines, showing 
the internal feat¬ 
ures of Trimerella, 
taken from the same 
work. We have 
also accorded recog¬ 
nition to the generic 
term Rhinobolus, 
which was made a 
synonym for Trim¬ 
erella in that work, 
but we now possess 
a considerably in¬ 
creased knowledge 
of this form, and 
have elsewhere 
quoted a subse¬ 
quently expressed 
a, deltidium. 
b, deltidial slope. 
c, deltidial ridges. 
d, areal borders. 
e, cardinal callosities. 
/, cardinal facet. 
(j, lozenge. 
ft, cardinal buttress. 
i, umbonal chambers. 
j, platform. 
k, platform vaults. 
l, median plate. 
m, median scars. 
n, anterior scars. 
o, lateral scars. 
p, post-median scars. 
r\ side j crescent. 
t, transverse scars. 
u, archlet (vascular sinuses). 
w, sub-cardinal scars. 
x, nmbo-lateral scars. 
j, platlorm. 
k, platform vaults. 
l, median plate. 
m, median scars. 
n, anterior scars. 
o, lateral scars. 
p, post-median scars. 
r\ side (crescent. 
s, end ) 
t, transverse scars. 
u, archlet (vascular sinuses). 
v, cardinal scars. 
w, sub-cardinal scars. 
opinion of Mr. Davidson’s, abandoning his earlier views on the value of this 
* On the Trimerellidse, a Palaeozoic Family of the Palliobranchs or Brachiopoda. By Thomas David¬ 
son, Esq., F. R. S., F. G. S.i etc., and Professor William King, Sc. D. Honoris Causa, Queen’s University in 
Ireland: Quart. Journ. Geol. Soc., vol. xxx, pp. 124-173, pis. xii-xix. 1874. 
