460 
Siphonodentalium, new British spe- 
cies of, 250. 
Siren pisciformis, on the regeneration 
of the limbs in, 149, 446. 
Skeleton, on the theory of the, 141, 
388. 
Somphoxylon, observations on the 
genus, 262. 
Soridia, new species of, 49. 
Spencer, H., on the theory of the 
skeleton, 388. 
Spherodorum. observations on the 
genus, with description of a new 
species of, 1. 
Spiders, new, 202. 
Spirifer cuspidatus, on the shell- 
structure of, 68. 
Spirosperfoum, observations on the 
genus, 14. 
Squirrels, synopsis of the, in the 
British Museum, 270, 323, 415. 
Steindachner, F., on new fishes, 79. 
Sticharium, description of the new 
genus, 63. 
Synclisia, observations on the genus, 
170. 
Syrrheonema, observations on the 
genus, 19. 
Tadunus, characters of the new ge- 
nus, 34. 
Teeniolabrus, description of the ge- 
nus, 79. 
Tamias, synopsis of the species of, 
434. 
Taygetes, new species of, 216. 
Terebratella Spitzbergensis, on the 
occurrence of, at Unst, 248. 
Terinos, new species of, 399. 
Thanasimodes, description of the 
new genus, 319. 
INDEX. 
Theridion, on some species of, new 
to Britain, 210. 
Thysanura, on the, 361. 
Tribonyx, on the species of the ge- 
nus, 122. 
Trichopterous pupz, a way to deter- 
mine, 384. 
Trivia, new species of, 215, 436. 
Trochus niloticus and T. maximus, 
on the different ages of, 97. 
Tympanocryptis, new species of, 52. 
Typhloplana, new species of, 300, 
Upeneus, new species of, 59. 
Ursus lasiotus, note on, 301. 
Utriculariz, on the aériferous vesicles 
of the, 389. 
Utriculus, new British species of, 
252. 
Verrill, A. E., on some remarkable 
instances of Crustacean parasitism, 
230; on the external characters of 
Elasmognathus Bairdii, 232. 
Verrucaria, on the species of, found 
in Lombardy, 106; new British 
species of, 256, 259. 
Victoria, on the recent zoology and 
paleontology of, 175. 
‘Vorticelle, on the phenomena of 
muscular contraction in the, 145, 
Waldheimia venosa, observations on, 
81. 
Walker, J. F., on a phosphatic a 
sit at Potton, in Bedfordshire, 118 
Wreden, R., on two new forms of 
plants parasitic on man, 385. 
Xenocharax, description of the new 
genus, 114. 
Zoological nomenclature, on the laws 
of, 233. 
END OF THE TWENTIETH VOLUME. 
PRINTED BY TAYLOR AND FRANCIS, 
RED LION COURT, FLEET STREET. 
