D4 i [MaARcH, 
Mr. Lea made some remarks on the subject of the periodicity of the Family 
Unionidae. He mentioned that some of the species matured and ejected from 
their oviducts the perfect shell in the autumn, others inthe spring, and some 
apparently in the winter. He mentioned that few observations had yet been 
made on this interesting branch of animal economy. He had himself made some 
observations many years since on the Uniones and Anodonte of our vicinity ; 
and his brother, T. G. Lea, had, at his request, made some interesting observa- 
tions of those in the vicinity of Cincinnati, part of which had been noted in the 
Transactions of the American Philosophical Society. He then read part of a 
letter from Mr. Joseph Clark of Cincinnati, in which he mentions having ob- 
served the periodicity of several species within the last six months. The Azo- 
donta edentu/a, Say, was found with oviducts fully charged in September, as 
were also Unio ellipsis, Lea, U. trroratus, Lea, U. securis, Lea, U. foliatus, 
Hild. and U. orbiculatus, Hild. In October he found the ova of the Unio multi- 
plicatus, Lea, more than half developed, and thinks they would have been ma- 
tured in the spring. In the Unio anodontoides, Lea, they were beautifully de- 
veloped, and would probably have been matured and-voided in the winter. The 
oviduets of the last species are bordered with a beautiful blue color. 
Thus Mr. Clark’s conclusions were the same as to the different periods of 
various species as Mr. Lea’s, and there cannot be a doubt but that the terms of 
the species differ according to their own law. 
March 30th. 
Vice President Bripces in the Chair. 
The Committee on Mr. Lea’s description of a new Unio, reported in 
favor of publication in the Proceedings. 
Description of a new species of Symphynote Unio. 
/ By Isaac Lea. 
Unio Cuminen. ‘Testa alata, plicata, triangulari, valdé compressa, posticé 
angulata, valdé inequilaterali; ala elevata, acuminata, margine crenulata; val- 
vulis subtenuibus, ante et post nates connatis; natibus, et alé posterioris basi 
apiceque undulatis; matibus’ compressis, ad apicem undulatis, haud prominenti- 
bus; epidermide nitida, tenebroso.viridi, perradiata; dentibus cardinalibus ba- 
_mellatis; lateralibus longissimis, lamellatis subcurvisque; ligamento celato; 
magarita alba et\iridescente. Ny) 
"Shell alate, plicate, triangular, very much compressed, angular behind, very 
inequilateral; wing high, acuminate, crenulate on the margin; valves rather 
thin, connate before and behind the beak; beaks, and the base and summit of the 
posterior wing undulateds; beaks compressed, undulated at the tip, not promi- 
nent ; epidermis shining, dark green, radiated all over; cardinal teeth lamellar ; 
lateral teeth very long, lamellar and somewhat curved; ligament concealed ; 
nacre white and iridescent. 
Habitat northern part of China, H. Cuming, Esq. 
Diam. .7, length 2.6, breadth 3.1 inches. 
This very beautiful and rare Undo is, in form and general outline, very much 
like the Dipsas plicatus, Leach, but they cannot be confounded with each other, 
as they belong to very distinct genera, the Dipsas having but one linear tooth 
in each valve, while the above described shell has perfectly well defined lamellar. 
cardinal teeth, double ings right-and-single in theteft valve. It also has long,Ja- 
mellar, lateral/teeth, double in the left and single in the right valve. It differs also 
in the folds, having them extending over the flattened side from the beaks, in this 
specimen, which is not half grown, to half the length of the shell. The folds 
