222 TRANSACTIONS OF THE [may 13, 
the reading of the minutes of the preceding meeting was omitted, 
and C. C. Trowbridge was appointed by the Chair to fill the office 
of Secretary pro tem. 
The Section of Biology at once organized. There being no 
business to be transacted, the Section listened to the first paper 
of the evening, “ The Cervical Plexus of the Cynomorphus A pes,’” 
by Dr. G. 8. Huntington, which had been deferred from the meet- 
ing of March 11. Remarks followed by Professors H. F. Osborn 
and, E. D. Wilson. Professor Britton asked to be excused, and 
appointed Professor Wilson to act as Chairman. 
Professor Osborn delivered his paper on ‘ The Relations of 
the Fauna of the Uinta Basin,” after which the Academy lis- 
-tened to the following : 
OBSERVATIONS ON THE YOLK-NUCLEUS IN THE 
EGGS OF LUMBRICUS. 
Gary N. CALKINS. 
In 1845 v. Wittich described a peculiar body lying in the cell 
plasm of the immature spider-egg (Lycosa, Tegenaria and 
Thomisus), and to this body Carus in 1850 gave the name of 
“ Dotterkern,” or yolk-nucleus. In 1864 the origin and appear- 
ance of the yolk-nucleus was carefully studied by Balbiani, and 
this led Milne-Edward in 1867 to give it the name of “ Vesicule 
de Balbiani.” Later observers have reported the presence of a 
yolk-nucleus in the eggs of many different classes of animals be- 
sides the spiders. It has been observed in the eggs of myrio- 
pods, birds, amphibians, fishes, lizards, molluscs, elasmobranchs, 
mammals, crustacea, echinoderms, bees and other insects, and 
finally in some of the worms [Trematodes]. The yolk-nucleus 
appears, therefore, to be a structure of general occurrence in 
the early stages of odgenesis. 
Many other names have been given to the yolk-nucleus. In 
addition to ‘ Vesicule de Balbiani” of Milne-Edward, it has 
been called “ Nebenkern,” “ archoplasm,” “ accessory nucleus,” 
and ‘ Dotterkonkrement.” None of these, however, improve 
upon the original name Dotterkern which, after 45 years, is still 
in use. A more explanatory name might be given to the “yolk- 
nucleus,” for it is not a nucleus, but on account of the priority * 
and of the significance which it has acquired, the term given by 
Carus is here retained. 
