INDEX 
SELACHII, in classification, 8. 
a” 157; S. Aapfi, 157 (Fig. 
161). 
Semon, R., 125, 181, 199, 200, 219. 
Sense organs, characters of, 46-56; 
tables of, 276-277; integument and 
integumentary sense organs, tables 
of, 278, 279. 
Sense of feeling, 46-48. 
Sensory canals in head of Chimera, 
30. 
Sensory tubules, v. Lateral line. 
Serranus, eggs of, 181 (Fig. 196), 186; 
development of egg of S. atrarius, 
208 (Figs. 269-283). 
Shad, v. Alosa. 
Shagreen denticle of - shark, 23-25 
(Figs. 20-22) ; of sting-ray, 24 (Fig. 
23), 25- 
SHARKS, movement of, 2; in classifi- 
cation, 7, 8; antiquity of, 9, 10, 72; 
gills of, 17 (Fig. 11), 19; spiracle 
of, 19; gill shields of, 20; skin, 
enamel, and dermal denticle of, 23- 
26 (Figs. 20-22) ; shagreen denticle 
of the Greenland shark (Lemargus), 
24 (Fig. 21); jaw of Port Jackson 
shark (Cestracion), 24 (Fig. 27), 
27; evolution of the dermal armour- 
ing, 25, 26 (Figs. 25, 26); unpaired 
fins of, 33, 34 (Figs. 39-43); caudal 
fin of, 36-39 (Figs. 45-47); lateral 
line of, 49, 50 (Figs. 61, 62), 51, 76; 
description of, 72-98 (Figs. 83-103) ; 
position of, 72; general anatomy of, 
73 (Fig. 83); skeleton of, 74-76 
(Fig. 84); sub-notochordal rod in 
skeleton, 76 (Fig. 85); integument 
of, 76; brain of, 76; nasal organ, 
eye, and ear, 76; renal and repro- 
ductive system of, 76; digestive 
tube, viscera, 77; heart, 77; clasp- 
ers, 77; fossil sharks described, 77- 
86 (Figs. 86-91); teeth of fossil, 86; 
recent sharks, 87—95 (Figs. 92-101) ; 
- affinities of, 95-98 (Fig. 103); eggs 
and breeding habits, 181 (Figs. 189- 
190), 183, 184; fertilization of eggs, 
297 
187 note; development of egg of, 
194-198 (Figs. 216-230); larval de- 
velopment of, 215-218 (Figs. 284- 
289); list of authors and their works 
on sharks, 238-244; comparison 
tables of the skeleton of, 252; skel- 
eton of Cestracion galeatus, 75 (Fig. 
84), 255; skull, jaws, and branchial 
arches, tables, 256; heart, tables, 
258 (Fig. 317), 260; gills, spiracle, 
gill rakers, and opercula, tables, 262 
(Fig. 11, p. 259); swim-bladder, 
tables, 264; genital system, tables, 
266; urinogenital ducts and exter- 
nal openings, 267 (Fig. 333), and 
tables, 270; plan of circulation in, 
tables, 268 (Fig. 338), 269; ab- 
dominal pores, tables, 271; brain of, 
272 (Fig. 341); sense organs of, 
tables, 276; integument and integ- 
umentary sense organs, tables, 279; 
comparison tables of the early devel- 
opment of, 280, 281. 
Siluroid, antiquity of, 9; affinity and 
phylogeny of, 147, 166 (171 A), 
171; South American Siluroid (Ca/- 
lichthys armatus), 172 (Fig. 178); 
eggs and breeding habits of, 181 
(Fig. 195), 185, 186 and note; 
heart, conus and bulbus arteriosus, 
tables of, 258 (Fig. 318). 
Siphostoma, eggs and breeding habits 
of, 186. 
SIRENOIDEI, in classification, 8. 
Skates, description of, 93-95 (Figs. 
100-102) v. Ray. 
Skeleton, v. Shark, Pleuracanthus, Chi- 
mzroid, Dipnoan, Ceratodus, etc. 
Skin defences, v. Dermal and Teeth. 
Skull of fishes, dermal bones of head 
root of Pleuracanthus, 84 (Fig. 90 
A); of Chimeroids, 113; resem- 
blances of skull of lung-fishes to 
Elasmobranchs, 128; of Dinichthys 
intermedius, 133 (Fig. 133 and Fron- 
tispiece) ; table of relations of skull, 
jaws, and branchial arches of, 254 
(Figs. 310-315), 256. 
