ZOOLOGY AND BOTANY, MICROSCOPV, ETC. 241 



eye-muscles appear as isolated elements (neurocytes) in the mesenchyme, 

 unconnected with the central nervous system or with the periphery. 

 They must be widely distributed in the* mesenchyme, and are rather 

 diffuse to begin with. There are several paths in the embryo, and one 

 of these becomes the main path. There is degeneration of some and 

 exaggeration of one. From this general position the author goes on 

 to give a detailed account of the development of the oculomotor, the 

 trochlear, and the abducens. 



b. Histolog-y. 



Mitochondria and Other Plasmic Structures.* — Jan Hirschler 

 discusses the widespread occurrence of Golgi's apparatus, which has 

 been described as an organellum of the cells of Vertebrates, Worms, 

 Molluscs, and Arthropods. He has found in Ascidians, Spongilla, and 

 Gregarines structures which correspond to Golgi's apparatus in their 

 chemico-physical nature, in their structure, and in their topographical 

 relations. He deals especially with the cells lining the stomach of 

 Ciona, with the flagellate cells of Spongilla and with Monocystis ascidise, 

 and describes in detail what these show in the way of mitochondria and 

 Golgi's apparatus. 



Minute Structure of Nerve-cells.| — Andreas von Sziits has made 

 a study of the nerve-cells of the earthworm, with particular reference to 

 the theory of Koltzoff and Gpldschmidt that the neurofibrils form a firm 

 internal framework, a sort of skeleton for the cell. The shape of the 

 nerve-cell is very intimately connected with the structure of the neuro- 

 fibrillar apparatus. In " nerve-cells " with an extremely elongated body, 

 which occur in the earthworm in the annular nerves and at the exit of 

 lateral nerves, there is no neurofibrillar meshwork, but the neurofibrils 

 run parallel along the cell. The roundish and pear-shaped ganglion 

 cells, on the other hand, are penetrated by a neurofibrillar meshwork. 

 Certain cells, in which the neurofibrillar meshwork or framework is 

 divided into two zones, show a perfect correspondence between the 

 shape of the framework and the shape of the cell. In elongated pear- 

 shaped cells the meshes of the internal framework are drawn out length- 

 wise, in spherical cells they are broader. It is concluded that the intra- 

 cellular neurofibrils form a supporting framework. 



Cortical Cell Lamination in Cerebral Hemispheres of Rodents. f. 

 A. E. B. Droogleever Fortuyn has studied the cortex of the cerebral 

 hemispheres in rabbit, mouse, rat, guinea-pig, squirrel, hare, and waltz- 

 ing mouse. The cell lamination and the situation of the areas generally 

 agreed in different rodents, although important differences occurred. 

 Some areas are characteristic of genera, others even of species. In some 

 rodents some areas show a not uniform structure, an irregular mixing of 

 two types of cell lamination. 



* Anat. Anzeig., xlvii. (1914) pp. 289-311 (1 pi. and 3 figs.). 



t Anat. Anzeig., xlvii. (1911) pp. 199-201. 



J Archives Neurol. Psychiatry, vi. (1914) pp. 221-354 (2 pis.). 



