— 154 — 
Enfin l'auteur a lui-même publié trois Index alphabé- 
tiques et méthodiques dont voici l'indication précise. 
«. — Index | to vol. I. to XI. of | Observations lon the | 
Genus Unio, | together with | Descriptions of New 
" Species of the Family Unionidae | and | Descriptions 
of New Species of the Melanidae, | Paludinidae, Heli- 
cidae, etc..., | [ Read before the American Philoso- 
phical Society and the Academy of Natural | Sciences 
of Philadelphia, from 1827 to 1863, | by | Isaac Lea, 
LE. D.etc, 
Philadelphia: | Printed for the Author | by T. 
K. Collins, 705 Jayne Street. gr. in-4°, 1867; 63 p. 
8. — Index | to vol. XII. | and Supplementary Index to 
vols. I. to XI. of | Observations | on the | Genus 
Unio, | together with | Descriptions of New Species 
of the Family Unionidae, | and | Descriptions of New 
Species of the Melanidae, | Paludinidae, Helicidae, 
etc..., | [ Read before the American Philosophical 
Society and the Academy of Natural | Sciences of 
Philadelphia, from 1827 to 1868. | by | Isaac Lea, 
LL, ,D., ete. vo EE 
Philadelphia : | Printed for the Author | by T. K. 
Collins, 705 Jayne Street. gr. in-4°, 1869, p. 23. 
y. — Index | to vol. I. to XII: of | Observations | on 
the | Genus Unio, | together with | Descriptions of 
New Species of the Family Unionidae, | and | Des- 
criptions of New Species of the Melanidae, | Paludi- 
nidae, Helicidae, etc..., | [Read before the American 
Philosophical Society and the Academy of Natural 
Sciences of Philadelphia, from 1827 to 1874. | by | Isaac 
Lea DL D IR oAMENr 
Philadelphia : | Printed for the Author. | Collins, 
Printer, 705 Jayne Street. gr. in-4°; 1874, p. 29. 
