444 



INDEX — GLOSSARY 



of, in pelecypods, 210, 215; spinous, 



in evolution, 363. 

 Shinarump formation, fossils from, 302 ; 



geologic age of, 302. 

 Ship barnacle, 305. 

 Shoulder-blade, see scapula. 

 Shrews, 379. 



Shrimp, brine, 285 ; mantis, 308. 

 Sicula, 113, 114, 115, 119, 120. 

 Sidney ia, 311, 314. 

 Sight, sense of, see eyes. 

 Sigillaria, 53, 54, 350; S. polita, 54; 



amphibians in, 352 ; fungus on, 40. 

 Sigillariostrobus, 54. 

 Sihca, 26; in animals, 26; in plants, 26; 



in plants (diatoms), 34; in Radiolaria, 



Q3, 94; solubility of, 12. 

 Silicification, 11. 

 Silicispongiae, 98. 

 Silurian, 407. 

 Silurian fossils figured, 41, 106, 120, 



137, 138, 155, 163, 249, 297, 304, 315, 



338. 

 Simia, 400. 

 Simiidas, 400. 



Sinistral shell, in gastropods, 241. 

 Sinus (plu. sinuses), a cavity or depres- 

 sion; blood, 212, 281; hyponomic, 



255 ; in cephalopods, 257 ; median, 



200, 201. 

 Siphon, of cephalopods, 251-252, 252, 



254, 255; of gastropods, 235, 235; 



of pelecypods, 208, 209, 20Q, 211. 

 Siphonal collar, 254. 

 Siphonal muscle, in pelecypods, 209, 214. 

 Siphonophora, 114, 121. 

 Siphuncle, of Belemnites, 271, 272 ; of 



cephalopods, 252, 254, 262, 264 ; of 



cephalopods compared, 261 ; of nauti- 



loids, ammonoids, belemnoids, and se- 



pioids compared, 261. 

 Siphunculata, 318. 

 Siren, 353. 

 Sirenia, 398 ; see also sea cows ; hind 



limbs of, 328. 

 Skates, 343. 

 Skeleton, see under the various classes; 



modification of during fossilization, 97. 

 Skin, preservation of surface characters 



of, 19. 

 Skull, bones of, in the cat, 324, 325 ; in 



the fish, 346 ; in the reptile, 367. 



Slickensides, resemblance to fossils, 21. 

 Slime-molds, 33. 



Slit band, in gastropods, 244, 244. 

 Sloths, extinct ground, 382 ; giant, in 



North America, 375 ; modern, 382. 

 Slugs, 243. 

 Smell, sense of, in crustaceans, 283 ; in 



gastropods, 237, 242 ; in mammals, 



335- 



Smelt, 348. 



Smilodon, 381 ; S. calif ornicus , 383. 



Snails, see gastropods. 



Snakes, 367 ; see also reptiles ; fore 

 limbs of, 328; hind limbs of, 328; ribs 

 in, 326. 



Social crowding, the massing of many 

 individuals during growth, as is the 

 habit of the sea mussel, Mytilns. 



Sockets, in brachiopod shells, 182, 183, 

 189, 203 ; in pelecypod shells, 209, 216, 

 223, 229. 



Soft-shelled crab, 308. 



Solenhofen lithographic stone, fossils 

 from, 370, 371 ; geologic age of, 370. 



Solenia (Greek solenion, a little pipe), 

 applied by Bourne to the canals lined 

 by endoderm, which branch out as 

 ofifshoots from the digestive cavities 

 of the polyps comprising a colony, as of 

 corals. These comprise the whole of 

 the ccenosarc or are merely tubes 

 running through it. From these 

 solenia arise, by budding, new polyps; 

 129. 



Solenopora compacta, 39. 



Solpugida, 316. 



Sori, 45, 46. 



Sparrow, compared to pterosaurs, 365. 



Spatangoids, 165. 



Specialization, extreme, in the extinction 

 of the species, 375. 



Spermatophyta, 43, 55-82 ; classifica- 

 tion of, 56 ; geologic range of, 408. 



Spermatophytes, the Spermatophyta. 



Sphagnum, 44. 



Sphenodon, 355. 



Sphenophy Hales, 55 ; geologic range of, 

 408. 



Sphenophy Hum, 55 ; S. schlotheimii, 55. 



Spicules, in corals, 128; in echinoderms, 

 148; in holothurians, 172 ; in sponges, 

 97, 100. 



