296 
MONTGOMERY. 
[Vol. XV. 
Carnoy (’84) distinguishes three kinds of nucleoli: ( 1 ) “nucle- 
oles nucleiniens,” which are parts of the chromatin network; 
( 2 ) “ nucRoles-noyaux,” which contain all the elements of a 
normal nucleus (namely, a membrane, chromatic filament, and 
nucleolar substance), while the substance in the remainder of 
the nucleus is allied to cytoplasm ; such nucleoli occur in 
Gregarines, large Radiolaria and Rhizopoda , Spirogyra, the asci 
of lichens, testicle cells of Littobius , and eggs of Pleurobrachia , 
Ascidia , and Nephthys; ( 3 ) “ nucleoles plasmatiques,” which 
contain no chromatin, but consist of a plastin network in 
which an albuminous enchylema is imbedded. 
Frommann (’84) studied fresh ganglion cells from the anterior 
horn of the medulla of the ox; their nucleolus shows “ eine 
Zusammensetzung aus feinen und derberen Kornchen und aus 
sehr kurzen Faden, mitunter auch einen netzformigen Bau mit 
theils ganz engen, theils etwas weiteren Maschen.” In the 
ganglion cells (of the ganglion Gasseri) of the rat, the nucleolus 
is usually homogeneous, as are those of the sympathetic ganglion 
cells of Bufo. 
R. Hertwig (’84), Actinosphaerium; in the resting nucleus 
there is one central nucleolus which consists of deeply staining 
nuclein and faintly staining paranuclein. The nucleolus is 
rarely spherical; when so, it consists mainly of nuclein, except 
for a small portion of paranuclein superimposed on the margin. 
In other cases the larger nuclein portion is of a curved dumb¬ 
bell shape, and “ gleichzeitig bildet das Paranuclein ein schwach 
gekrummtes Stabchen, dessen Kriimmung zur Krummung der 
Nucleinmasse senkrecht gestellt ist.” The connecting portion 
of the dumb-bell may disappear, “ so dass sich zwei Nucleoli 
bilden, welche von einander durch ein queres Stabchen Para¬ 
nuclein getrennt werden. . . . Hiermit beginnen die plurinu- 
cleolaren Kerne, wie sie fur gewohnlich bei Actinosphaerium 
beobachtet werden.” In most nuclei there lies a mass of from 
six to twenty nucleoli, which are smaller as they become more 
numerous: “ Hier ist es sehr schwer festzustellen, was aus dem 
Paranuclein geworden ist, und . . . bin ich zu dem Resultat 
gekommen, dass es als ein Korn im Centrum des Haufens von 
Kernkorperchen ist, dass es mit einem Fortsatz an jedes 
