146 W. B. SCOTT, 
Pretiminary Account of the Devetorment of the Lampreys, 
By W. B. Scorr, M.A., Assistant in Paleontology, 
Princeton, New Jersey. 
For nearly a year (1879-80) I was occupied in the laboratory 
of Professor Gegenbaur in working out the development of the 
Lampreys, the results of which investigations will appear shortly 
in a more extendedform. It seemed, however, desirable to give 
a preliminary account of the results which have been obtained, 
in order, as far as possible, to direct the attention of mor- 
phologists to the general character of the development of this 
important and little understood group of Vertebrates. Professor 
Gegenbaur very kindly placed at my disposal the splendid mate- 
rial which was so laboriously and skilfully collected and prepared 
by the late Dr. Calberla. ‘This consists of an immense series of 
preserved embryos and larve, and of many thousand prepared 
sections ; and, in addition to these, I have further obtained a 
fine series of larvee, for which I am indebted to the friendly offices 
of Professor Wiedershein. 
Since the publication of my little article in the ‘ Zoologischer 
Anzeiger,’ 1880, No. 63, I have obtained an article by Pro- 
fessors Kupffer and Benecke,! which has made it necessary to 
alter slightly, though not essentialiy, the statement concerning the 
maturation of the ovum contained in my paper. According to 
Calberla? the conversion of the germinal vesicle into the female 
pro-nucleus takes place simultaneously with the metamorphosis 
of the larva into the sexual animal. I was led to doubt this 
statement for many reasons, and believed that the germinal vesicle 
persisted unchanged until nearly the time of laying. This result 
is fully confirmed and extended by those of Kupffer and Benecke. 
According to these observers there are two polar bodies formed, 
one before and one after impregnation. ‘Ibe one which I men- 
tioned as being present in the ovum already segmented into four 
corresponds to the latter of these bodies. The first of them 1 
did not find, as no fresh material of the proper stage was ac- 
cessible to me. According to Kupffer and Benecke this first 
polar body is a nucleus-like body surrounded by a membrane, 
and embedded in granular protoplasm; it is nearly always ec- 
centric in position. The authors just mentioned consider it 
highly probable that this body is a derivation of the germinal 
' C. Kupffer and B. Benecke, ‘ Der Vorgang der Befruchtung am Hi der 
Neunaugin,’ Konigsberg, 1878. 
2 HK. Calberla, ‘Der Befruchtungsvorgang beim Hi von Petromyzon 
Planeri. Zeitschr. fiir wissensch, Zoologie,’ B, xxx. 
