OVARY AND OVARIAN EGG OF ANOPHELES 431 
pennis is almost entirely the product of the nucleolus. Now 
Bambeke considers that the yolk nucleusof Pholeus is nuclear 
in origin, and other authors are of the same opinion with regard 
to other animals. Thus Korschelt (18) observes, ‘ Wenn man 
sieht, welche complicierte Gestaltung dem aus concentrischen 
Schichten gebildeten Dotterkern mancher Spinnen zukommt, 
moéchte man ihn fiir einen bedeutungsvollen Bestandtheil des 
Kernes halten und ihn gewiss nicht mit demsoeben besprochenen 
‘** Dotterkern ’’ der Amphibien zusammenwerfen.’ 
In further support of the theory of the nuclear origin of the 
Corpuscles of Balbiani, Bambeke remarks: ‘ Des que la forme 
de batonnet a fait place a celle de bourrelet ou de cupule, 
la constitution du corps vitellin se montre tres semblable, voire 
méme identique, a celle de la tache germinative. . . . Cette 
frappante analogie entre la constitution de ces éléments ne four- 
nit-elle pas un argument de plus en faveur de l’origine nucléaire 
du corps vitellin ? ’ 
Having shown that the body with which he is dealing is 
probably nuclear in origin and is comparable to the nucleolus, 
Bambeke proceeds to give his reasons for believing that the 
body is a true ‘corps vitellin de Balbiam’. These may be 
summarized as follows : 
1. Situation near germinal vesicle. 
2. Affinity for colours similar to that of the nucleolus. 
3. Presence of vacuoles. 
4, Constancy of the character. 
5, Appearance at commencement of growth. 
6. Final degeneration. 
All these characters are also true of the branching nucleus 
in A. maculipennis except that in nos. 1 and 2 similarity 
of position and character is replaced by identity. The presence 
of vacuoles is only found in the earliest stages of the nucleus, 
but this is not actually an important difference from the yolk 
nucleus of Pholeus, as in the latter the vacuoles disappear 
before it degenerates, so that actually this is a further indication 
of the similarity existing between the two structures. Is it 
