6 
LEA, ISAAC, LL.D.—(Continued.) 
Description of a new species of Helix from California, and a 
new Characteristic Form of certain American Colimaces. (Read 
March dth, 1852.) 
Vol. x, p. 303. 1853. 
Notre.—It will be seen that the Date of Reading of many of Mr. Lea’s Papers preceded by several 
years, that on the Title-page of the Volume in which they were issued. The Transactions were pub- 
lished in Parts, but afford no internal evidence of the date of their issue, which has unfortunately 
resulted in much uncertainty in regard to the priority of many of the specific names. Mr. Lea has 
given in the Proceedings of the Academy of Natural Sciences, Vol. vii, p 236, a list of dates of publica- 
tion, which I have deemed it important to insert here.—(See References in Parenthesis.) I have also 
given the date on which some of the articles were issued in the Proceedings of the Philosophical 
Society. Mr. Lea claims that the date of publication of a paper, rs that on which itis read. 
IN PROCEEDINGS OF THE ACADEMY OF NATURAL SCIENCES, PHILADEL- 
PHIA. ; ; 
Including the principal remarks made by Mr. Lea, before the Society. 
Letter from Mr. Lea, respecting change of orthography in spe- 
cific names of Unionidw. Dated October 8th, 1842. (Read No- 
vember Ist, 1842.) 
Vol. i, No. 20-21, p. 215. December, 1842. 
On the Genus Acostza, D’ORBIGNY. (Communicated October 
21st, 1851.) 
Vol. v, No. 11, p. 277. October, 1851. 
~ Remarks on the Periodicity of the Family Unionidz. (March 
23d, 1852.) 
Vol. vi, No. 2, p. 54. April, 1852. 
Description of a new species of Symphynote Unio. (Read 
March 9th, 1852.) 
Vol. vi, No.2, p. 54. April, 1852. 
Remarks on the Classification of the Naiades by their Anato- 
tomical Differences. (April 6th, 1852.) ; 
Vol. vi, No. 2, p. 57. April, 1852. 
Notice of the Mya nodulosa. woop. (June 14th.) 
Vol. vi, No. 9, p. 368.. June, 1853. p 
Letter to Dr. Leidy, on Castalia sulcata.and other Naiades. 
(Read August 2d.) 
Vol. vi, No. 10, p. 376. August, 1853. 
