296 
Pristis, antiquity of, 9; description of, 
gt (Figs. 98 and 984A); affinities 
of, 96-98 (Fig. 103). 
Pristiurus, \arval development of, 215, 
216 (Fig. 284). 
Protocercy, 35. 
Protopterus, swim-bladder of, 22 (Fig. 
18); anatomy of, 116 (Fig. 121); 
paired fin structure, 118 (Fig. 122), 
119; jaws and skull, 119 (Fig. 
122 A); account of, 126 (Fig. 
129 A); Coccosteus compared with, 
131; heart, conus and bulbus arte- 
riosus, 285 (Fig. 325); comparison 
tables of heart, etc., 260; gills, 
spiracle, gill rakers, and opercula, 
tables, 261; digestive tract, tables, 
262 (Fig. 329), 263; swim-bladder, 
tables, 264, 265 (Fig. 18); circula- 
tion in, tables, 269; excretory sys- 
tem and urinogenital ducts, 270; 
abdominal pores, 271; brain of, 273 
(Fig. 343); central nervous system 
tables, 275. 
Psammodus, dentition, 86. , 
Psephurus, 160-163; P. gladius, 162 
(Fig. 166.4), 
Pseudopleuronectes, vy. Flounder. 
Pteraspis, antiquity of, 9; described, 
67 (Figs. 74, 76, 77). 
Pterichthys, antiquity of, 9; described, 
69 (Figs. 80-82); Arthrodira associ- 
ated with by Traquair, 130. 
Putnam, 182. 
Pycnodont, 157, 158. : 
Rabbit-fish, v. Lagocephalus. 
Rabl, C., 146; phylogenetic table of, 
compared, 283. 
Raja, v. Ray. 
Rat-fish, v. Chimera. 
Ray, in classification, 8; antiquity of, 
9; shagreen of, 24 (Fig. 23); de- 
scription of, 93-95 (Figs. 100-102) ; 
barn-door skate (2. devis), 94 (Fig. 
101); affinities, 95, 96, 98 (Fig. 
103); eggs and breeding habits, 181 
(Fig. 189 4), 183, 184. 
INDEX 
Recent sharks, v. Sharks. 
Relationships, v. Affinities, under the *% 
family and species. 
Respiration, vy. Aquatic breathing. 
Retzius, G., phylogenetic table of, com- 
pared, 282. 
Rhina, 91 (Fig. 97); affinities to 
shark, 96, 98 (Fig. 103); brain of, 
tables of, 272 (Fig. 341). 
Rhinobatus, antiquity of, 9; descrip- 
tion of, 93 (Fig. 100); affinities to 
shark, 98 (Fig. 103). 
Rhyncodus, mandibular of, 106 (Fig. 
III), 111. 
Riickert, J., 187, 
Ryder, J. A., 31, 37, 115. 
Salensky, W., 214 note. 
Salmonid, antiquity of, 9; eggs and 
breeding habits, 186; skull and 
branchial arches, table of, 254 (Fig. 
315), 257: 
Sandalodus, dental plates of, 24 (Fig. 
28), 28. 
Scales, 23; of Teleost, 24 (Fig. (31)5 
degeneration of, 26. 
Scaphaspis, 66 (Fig. 77), 67. 
Scaphirhynchus, 160; S. platyrhyncus, 
162 (Fig. 166). , 
Scomberomorus maculatus, 2, 3 (Fig. 
3); front view of, 4 (Fig. 4); lines 
of, 5 (Fig. 6). 
Sculpin, barbels of, 46, 47 (Fig. 57). 
Scyllium, shagreen of, 24 (Fig. 22), 
25, 90; eggs of, 181 (Fig. 189), 
183, 184 and note; development of 
egg of, 193 (Figs. 216-230); larvae 
of, 215, 216 (Figs. 285-287); skull, 
jaw, and branchial arches of, 254 
(Fig. 310), 256. 
Sea-bass, v. Serranus. 
Sea-cat, v. Chimera and Callorhyn= 
chus. 
Sea-horse, v. Hippocampus. 
Sea-raven, v. Hemitripterus. 
Sea-robin, v. Prionotus. 
Seal, fish-like form of, 6. 
Selache, gills of, 20. 
a 
