DESCRIPTIVE REMARKS. 
ire. el 8s 
Cepnatopopa. Order TETRABRANCHIATA. 
Shell external. 
B 
Le | 
J 
Be 
ae 
a 
EJ 
= 
LE) 
ets 
LE 
iS la 
s 
Lip) 
EG 
Le 
ee 
Ne) 
NavTILus Pompi.ius (recent), reduced to one-third of natural size. OrtHoceRas (extinct). 
Section of Shell, with the animal occupying the outer chamber. Section showing : 
a. The Mantle. a. Septa. 
6. The Hood. 6. Siphuncle. 
ce. The Tentacles. 
d, The Funnel. 
e. The Eye. 
Jf. Nidamental gland. 
g- Septa. 
h. Siphuncle. 
(After Woodward.) 
The Crustacea of the Carboniferous formation show a considerable 
declension from that of the Lower Paleozoic, especially with regard 
to the extinct order of Trilobites, of which only three genera remain, 
Phillipsia, Griffithides, and Brachymetopus. B. Ouralicus, Pl. 41, 
g. 1, a-d, is a small species found in Carboniferous Limestone, 
Derbyshire, and at several localities in Ireland. Phillipsia pustulata, 
tig. 2, a—-c, is a frequent fossil in Carboniferous strata from the lowest 
division to the Coal Measures; Grifithides globiceps, fig. 3, a, b, is also 
lxxil 
