G. C. Broadhead— Origin of the Less. 427 
captured by the dip net at the surface of the ocean that it is 
not possible to identify them as oysters without tracing them 
from the egg. The oldest ones which I succeeded in raising in 
aquaria were almost exactly like the embryos of Cardium, 
figured by Lovén. 
7. The ovaries of oysters less than 14 inches in length, and 
probably not more than one year old, were fertilized with 
semen from males of the same size, and developed normally. 
An illustrated paper on the embryology of the oyster, with 
a detailed account of my obseryations, will be published, 
only, in the Report of the Maryland Fish Commission for 
Baltimore, Nov. 5, 1879. 
Art. LIL— Origin of the Less; by G. C. BROADHEAD. 
Waar facts Baron yon Richthofen may have observed in 
Eastern Asia tending to form his opinion of the origin of 
the loss I have not had the opportunity to examine; but 
from careful observations of the loess in many places along 
and adjacent to the Missouri and Mississippi rivers, I cannot 
refer these deposits to wolian or wind-drift agency. Professor 
Hilgard, in his article in this Journal for August, conveys to 
times be traced for several hundred feet horizontally, forming 
beds from a few inches to more than a foot in thickness. 
1 be concretions are either united to each other or often sepa- 
rate 
Seventy feet height. When not quite as cohesive, time will 
Wear off the fot oe points, and produce rounded mammillated 
