ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
43 
which lies between the future mid-intestine and the beginning of tho 
tail, and has an interesting history. It loses connection with the other 
parts and becomes modified into “ hsemenchyme ” tissue, absolutely re- 
sembling the adenoid or reticular connective tissue from which the sub- 
mucosa arises. 
Prof. Hoffmann had previously concluded that the cardinal veins 
were direct diverticula of the sinus venosus. But this is true only of 
the common cross stems, by which the anterior and posterior cardinals 
join the sinus venosus. The cardinal veins arise as segmental diverticula 
of the aorta which form a blood-sinus around each cranial and spinal 
nerve. Of these diverticula the proximal portions may be regarded as 
arteries, the distal portions as veins, and it is from the fusion of the 
latter that the cardinal veins arise. As both the sinus venosus and the 
aorta arise from the archenteron, the same is now shown to be true 
(though more indirectly) for the duct of Cuvier and the cardinal veins. 
Maturation of the Ovum of the Lamprey.* — Herr K. Y. Herfort 
believes that all who have previously investigated the fertilization of 
the ovum in the lamprey have failed to discover the true germinal vesicle 
and polar bodies. The mature but unfertilized ovum shows (1) a thin 
layer of formative plasm or pole-plasm at the animal pole, (2) an alveolar 
cortical zone, (3) a lateral insinking of the periphery containing the 
first polar body and showing beside this a spindle and a distinct radia- 
tion, (4) an outer denser vitellus, and (5) an inner looser vitellus. Im- 
mediately after fertilization the pole-plasm shows the well-known 
amoeboid protrusion between the ovum and the surrounding membrane, 
the alveolar cortical zone disappears ; laterally in the yolk and at some 
distance from the periphery lies the spindle ; the first polar body has 
degenerated and the depression in which it lay vanishes. The second 
polar body is smaller than the first, and lasts longer. What Kupffer 
and Bohm called the polar bodies are hyaline protrusions of the pole- 
plasm artificially separated. 
£. Histolog-y- 
Minute Structure of the Cell-t — Dr. F. Reinke is enthusiastic in 
regard to the results of using his lysol method. He confirms the ob- 
servations of others as to (1) the likeness between nucleoli and nuclear 
membrane, (2) the reticular structure of the nuclear membrane, and 
(3) the complicated structure of the so-called nuclear sap ( Kernsaft ) 
which seems often to consist of threads with enclosed granules. He 
corroborates previous hypotheses, e. g. the existence of polar areas in the 
structure of the resting nucleus. New results are also attained, especially 
this, that each kind of tissue is characterized by a specific differentiation 
of the nuclear structure. 
Interactions between Cell-substance and Nucleus.f — Dr. W. Roux 
noted some years ago that the form of the protoplasmic masses within 
the cell had a directive influence on the nuclear spindle. In the course 
of his researches in experimental embryology he has gathered some fresh 
facts. The materials of the cell-substance are disposed in relation to 
* Anat. Anzeig., viii. (1893) pp. 721-8 (7 figs.). f Tom. cit., pp. 639-46. 
X Zool. Anzeig., xvi. (1893) pp. 412-6. 
