SCIENTIFIC INDEX. eli 
radians, 958. 
richmondensis, 938. 
schmidti, 936. 
sptrillum, 986. 
stamineum, 932, 935, 940. 
striatum, 936. 
subtilistriatum, 940. 
Raphistomida, 930, 931, 938, 944, 945, 1005, 1023. 
Raphistomina, 941, 931, 932, 933-935, 937-942, 944, 
945, 992, 993. 
denticulata, 943. 
lapicida, 942, 932, 934*, 943. 
laurentina, 941, 943. 
modesta, 943. 
rugata, 944. 
Rhineoderma, 960. 
Rhombina, 632. 
Rhynchotrema inequivalvis, 912. 
increbescens, 912. 
Rhynchotreta capax, 677. 
Rhytimya, 618, 487, 517, 526, 619, 620. 
lunulata, 620. 
producta, 618, 619. 
sinuata, 619. 
Ribs of trilobites, 698. 
Schmidtella, 639, 632, 640, 642. 
affinis, 641, 642, 653. 
brevis, 642, 
crassimarginata, 640, 639, 641, 690. 
incompta, 642, 641. 
var. subeequalis, 642. 
subrotunda, 643, 641, 685. 
umbonata, 641, 642, 643. 
Saffordia, 625, 487, 621. 
modesta, 627. 
sulcodorsata, 626, 627. 
ventralis, 626, 625, 627. 
Salpingostoma, 897, 815, 850, 851, 858, 883, 885, 886, 
888, 898, 899, 904, 915. 
buelli, 9OO, 851, 898-902, 904. 
var. kentuckiensis, 901, 851. 
canadensis, 851. 
compressa, 851. 
expansa, 901, 851, 902. 
fraternus, 851. 
imbricatum, 902, 851. 
locator, 851. 
megalostoma, 851. 
richmondensis, 903, 851, 893, 895. 
sculptilis, 9O2, 851, 898, 904. 
Sannionites, 775. 
Sanguinolites, 619, 486. 
Sanguinolitide, 486. 
Sarepta, 583. 
Scalites, 933, 931, 934, 935, 944. 
angulatus, 933%. 
tropidophora, 1081. 
Scaphopoda, $18, 815, 817, 845. 
Scenella, 837, 820, $22, 823, 825, 827, 838, 841, 842. 
affinis, $40, 841. 
var. obsoleta, 841. 
beloitensis, $39, 838, 841, 842. 
compressa, $40, 841. 
magnifica, $39, 840, 842. 
montrealensis, 841, 838, 840. 
obtusa, $41, 842. 
radialis, $41, 837. 
reticulata, 822, 837. 
superba, $38, 839-842. 
Schizodus, 486. 
Schizolopha, 991, 947, 949, 952. 
mooresi, 992, 952, 991. 
textilis, 992, 948, 952, 991. 
Scissurella, 815. 
Sedgwickia, 619, 487,618, 621. 
lunulata, 619. 
Seelya, 1011, 958, 989, 1008, 1009, 
difficilis, 1009. 
lirata, 988. 
var. obsoleta, 989. 
mundula, 1012. 
ventricosa, 1009*, 958, 1012. 
Segments of tribolites, 697. 
Sepia, 761. 
Septa of Cephalopoda, 761. 
Shell of Cephalopoda, 763; of Gastropoda, 814. 
Silurian, Cephalopoda of Lower, 760-812; Gastro- 
poda of Lower, 813-1081; Lamellibranchiata of 
Lower, 475-628; Ostracoda of Lower,. 629-693; 
tribolites of Lower, 694 -759. 
Sipho of Cephalopoda, 765, 762. 
Siphonida, 486. 
Solarium caillaudianum, 939. 
Solen, 517. 
Solenidee, 487. 
Soleniscus, 1079. 
Solenomya, 530, 486. 
Solenomyide, 486. 
Solenopsis, 487. 
Solenospira, 1021, 959, 1013, 1022. 
pagoda, 1022, 1023. 
prisca, 1022, 1023. 
Spathella, 485. 
Spenotus, 486. 
Spherocoryphe, 737. 
robusta, 738. 
salteri, 738. 
Sphenolium, 628, 487, 517, 531. 
cuneiforme, 623. 
parallelum, 624. 
striatum, 624, 625. 
Spines, caudal, 698. 
genal, 697. 
Squid, 761. 
Stachella, 857. 
bifrons, 857. 
Stenoloron, 960. 
Stenotheca, 842, $22, 827, 837, 838, 843, 845, 846, 
859. 
cornucopia, 822. 
elongata, 843. 
exserta, S42. 
rugosa, §42, 843. 
var. lens, 843. 
unguiformis, $43, 826. 
Straparollina, 1024. 
