168 Miscellanies. 
At what age it is formed in our young Naiades, I am unable 
to decide. I have discovered it to exist in many instances when 
they had not yet formed the first concentric line of growth on 
their shells, and therefore conclude that they attach themselves 
to some fixture, soon after they are ejected from the oviduct of 
the mother. 
It is probably continued, unless accidentally destroyed, until the 
animal attains strength sufficient to retain its position by grap- 
pling the sand and pebbles with its extended and curved foot. 
The length of this byssus when unextended, is from four to six 
inches; the size that of the finest sewing silk, and the strength 
is so great that it will resist the force of the strongest current of 
water, even after the animal is raised out of its bed. 
'The species we found thus attached in this locality, were prin- 
cipally the U. zigzag, elegans, dehiscens, ebenus, crassus, folia- 
tus, pyramidatus, crassidens and gibbosus. I believe, however, 
that every species has the power of forming a byssus when 0¢- 
casion requires it. 
Cleveland, March 10, 1840. 
MISCELLANIES. 
: DOMESTIC AND FOREIGN. 
= 3 eS : Soha SEE . oe 
Brstrocraruicat Notices.—Brief notices of recent Botanical 
works, especially those most interesting to the student of North 
American Botany. [{Communicated. | 
1. DeCandolle, Prodromus Systematis Naturalis Regni Vegetabt- 
lis, §c., Pars 7ma. Sectio posterior. (Paris, 1839).—The second 
part of the 7th volume of DeCandolle’s Prodromus—with which our 
notices may appropriately commence—was published at the very 
close of the last year, and comprises the following orders, viz. Sty- 
lidee, Lobeliacee, Campanulacee, Cyphiacee, (a very small orders 
founded on the Cape genus Cyphia, and here first proposed by Alph. 
DeCandolle,) Goodenoviee, Gesneriacee, Napoleonee, Vaccine@s 
Ericacee, Epacridee, Pyrolacee, Francoacee, and Monotropeé- 
Of these, the Lobeliacee, Campanulacee, and Cyphiacee were elabo- 
rated by Prof. Alphonse DeCandolle, the well known son of the dis+ 
tinguished author; the Vaccinee by Prof. Dunal of Montpelier ; and 
the tribe Ericex (the Heath-tribe) was prepared by Mr. Bentham. It 
