ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 45 



the moment when the first follicular cells are about to appear, we see 

 that the germinal vesicle has but one highly refractive nucleolus, 

 set in a hyaline liquid in which coloured granules are more or less 

 scattered — the chromatin grains. It is to be noted that if fresh ova 

 are observed in the blood of the animal, the grains only appear after 

 the addition of reagents ; this leads us to think, with Flemming, that 

 the nucleolar and the chromatin-grauules are not of exactly the same 

 nature. Outside the vesicular membrane and in the yolk of the egg 

 there are granules, sometimes in considerable numbers, which have 

 exactly the same aspect, form, and reactions as the granules within it. 



When we examine ova in which the follicular cells are in course of 

 formation we see that, near the vesicle, the chromatin granules of the 

 yolk are multiplying and aggregating ; so that they form a refractive 

 mass. At first this mass is perfectly homogeneous, but, as it becomes 

 organized, one, two, or even a larger number of more highly 

 refractive granules become apparent. The corpuscles thus formed 

 by the aggregation of the chromatin granules vary a good deal in 

 form ; they may touch the wall of the germinal vesicle, but it is quite 

 clear that they are altogether outside it, and that they have no 

 relation to its contents. 



Sabatier is convinced that the appearances seen by Fol are due 

 to an extroflexion of the wall of the vesicle, and he thinks that Fol's 

 own figm'es, which are very exact, suffice to demonstrate this point. 

 After further criticisms on the criticisms of Fol and Roule, some 

 more general problems are considered. The author asks whether it 

 is true that chromatin is only found normally in the nucleus, and 

 whether every chromatinated portion in the protoplasm has arisen 

 from fragments of the nucleus. He thinks not, basing his view 

 chiefly on the consideration that we do not know what chromatin 

 really is, and that all we can say is that it represents a condition of 

 protoplasm which possesses a more marked affinity for certain colouring 

 substances, and is sometimes also a little more refractory than the 

 rest. He is inclined to regard chromatin as the result of a modifica- 

 tion introduced into the constitution of the cell, and found in rela- 

 tion with the nutrient activity of its elements ; if this be so, there is 

 nothing astonishing in our finding that, in certain cases, the chromatin 

 is met with, and that in considerable quantities, not only in the 

 nucleus but also in the protoplasm of the cell ; this hypothesis may 

 explain the intracellular plexuses described by Klein. Sabatier 

 firmly believes that in the young eggs of Tunicates a notable quantity 

 of chromatinated substance appears in the yolk, that it increases 

 from the periphery to the centre, and so attains its maximum near the 

 germinal vesicle. Too much importance seems to have been attributed 

 by Flemming to the chromatin. 



Two New Species of Simple Ascidians.* — M. Eoule describes 

 two new species of simple ascidians belonging to the family 

 Phallusiadeee. 



For the first of these he proposes the name Ciona Edwardsi, and 



* Comptes Eeudus, xcis. (1884) pp. 613-4. 



