SCIENTIFIC INDEX. exli 
strongi, 852. 
subquadratus, 1026, 1028. 
subrugosus, 1026. 
subumbilicatus, 1026. 
triquetrus, 1023. 
tuba, 1044. 
umbilicatus, 1026. 
uniangulatus, 1025. 
walmstedi, 1025. 
Euphemus, $55, 856, 868, 875, 876, 915, 922, 924. 
apertus, 855. 
carbonarius, 855. 
indicus, 855. 
laevis, 855. 
lenticularis, 855, 
nodocarinatus, 855. 
orbigyanus, 855. 
urii, 855. 
Eurychilina, 658, 631, 632, 650, 659, 661, 664. 
zequalis, 659. 
granosa, 659, 661. 
longula, 659, 662. 
manitobensis, 659, 662. 
obesa, 659, 663. 
reticulata, G6O, 658, 659, 662. 
var. incurva, 660, 661. 
striatomarginata, 659, 663. 
subequata, 663, 648, 659, 664. 
subradiata, G61, 659, 662. 
symmetrica, 663, 
ventrosa, 662. 
Eurymya, 512, 485, 501, 504, 524, 628. 
alata, 513. 
plana, 612, 513. 
subplana, 513. 
Eurystomites, 811. 
undatus var. occidentalis, $11, 812. 
Euthydesma, 487. 
Eyes of trilobites, 697. 
Facial suture of trilobites, 697. 
Fissurella, 815. 
Fissurellide, 930, 947. 
Foot of Gastropoda, 813. 
Form of shell, in Cephalopoda, 63; in Gastropoda, 
815. 
Frontal lobes, 697. 
Furrows, dorsal, 697; lateral, of glabella, 697. 
Fusispira, 1075, 815, 1066, 1070, 1073. 
angusta, 1079. 
var. Subplana, 1079. 
convexa, 1077, 1078. 
inflata, 1075, 1076. 
var. ventricosa, 1075. 
intermedia, 1076. 
nobilis, 1078, 1073. 
planulata, 1078, 1073. 
schucherti, 1076, 1077, 1078. 
spicula, 1073. 
subbrevis, 1076. 
subfusiformis, 1077, 1078. 
Sulcata, 107 , 1078. 
terebriformis, 1077, 1078. 
ventricosa, 1075. 
Gastropoda, 475, 480; chapter on, 813-1081. 
Genal angle of trilobites, 697; spines, 697. 
General characters of the Lower Silurian Cephalo- 
poda, 763. 
Gerasaphes, 710. 
ulrichana, 710*, 705, 711*. 
Glabella of trilobites, 696; furrows of, 697. 
Glossites, 486. 
Glossophora, 817. 
Glyptocardia, 486. 
Glyptodesma, 485. 
Gomphoceras, 796. 
cassinense, 796. 
Gomphoceratide, 796. 
Goniatites intumescens, 756. 
Gonioceras, 794, 766. 
anceps, 794, 795, 812. 
lambi, 793. 
occidentale, 795, 812. 
Gonioceratide, 794. 
Goniodon, 486. 
Goniophora, 485, 504. 
Goniostropha, 1013, 1012, 1014. 
bachelieri, 1013. 
chalmasa, 1013. 
Gosseletia, 960. 
Gosselettia, 485. 
Grammysia, 625, 487, 621. 
Grammysiide, 623, 487. 
Groove, articulating, 697; pleural, 697. 
Gymnosomata, 818. 
Gyroceras, 811, 803. 
duplicostatum, $11, 812. 
Gyroma, 960, 961. 
Gyronema, 1054, 1046, 1056, 1057. 
duplicatum, 1055, 1056. 
liratum, 1056, 1046. 
pericarinatum, 1046. 
pulchellum, 1054, 1046, 1055, 1056 
semicarinatum, 1055. 
Halliella, 656, 632, 674. 
labiosa, 656. 
retifera, 656. 
sculptilis, 656. 
seminulum, 656. 
Hallina nicolleti, 615. 
Haliotide, 930. 
Haliotis, 844. 
Harpes, 755, 756. 
consuetus, 756. 
escanabe, 758. 
minnesotensis, 754, 757. 
venulosus, 756*. 
Harpina, 755, 757. 
antiquata, 758. 
minnesotensis, 755*, 757. 
ottawensis, 757. 
prima, 756*. 
rutrellum, 757, 758*. 
Helcion, 820, 827. 
Helcionopsis, 826, 820, $21, 824. 
fissicostata, 821, 
