ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 511 



posterior to the heart in the middle line. The pronephros is distinctly 

 of Amphibian type ; it consists of two tubules which open internally 

 into the coeloni by nephrostomes, and externally into the segmental duct. 

 Each is furnished with a glomerulus. Later, pronephric chambers of 

 ccelomic origin are formed into which the nephrostomes open. These 

 preliminary notes confirm the view of the closeness of the connection 

 between Dipnoi and Amphibia. 



b. Histology. 



Absorption of Anilin Stains by Living Cells.* — E. Overton shows 

 that there is a far-reaching parallelism between the rapidity with which 

 living animal and vegetable cells take up anilin stains, and the readi- 

 ness with which these are dissolved in solutions of cholesterin, lecithin, 

 protagon, and cerebrin, or are absorbed from aqueous solution by lecithin, 

 protagon, &c, in suspension. Since lecithin and cholesterin seem to be 

 present in all living cells, he argues that it is very probable that the 

 osmotic qualities of the cell depend upon their occurrence. 



Basilar Granulations of Cilia.f — P. Vignon brings forward fresh 

 facts supporting his conclusions that the basilar granulations of cilia 

 do not form true organs of the cell, like the centrosomes, and that they 

 have not any motor role in the ciliary movement, which can only be 

 called protoplasmic. 



Ganglion Vestibulare of Mammals.:}; — Dr. G. Alexander has studied 

 the portion of the ganglion acusticum to which this name is given in 

 various mammals, and finds that it consists of two parts connected by an 

 isthmus containing small ganglion cells and nerves. Both parts of the 

 ganglion contain bipolar nerve cells, whose central processes constitute 

 the upper and middle roots of the auditory nerve. The peripheral pro- 

 cesses form the utricular and ampullar nerves. The ganglion vesti- 

 bulare is connected by nerve-fibres with the ganglion geniculi. 



Structure of Retina.§ — H. M. Bernard has continued his researches 

 on the histology of the amphibian retina, the present instalment being 

 devoted to the minute structure of the rods. He finds that they are 

 specialised protrusions of the retina, consisting of extremely delicate 

 protoplasmic vesicles, each divided by a transverse membrane into an 

 inner and an outer compartment. These vesicles, especially the outer, 

 are traversed by a staining reticulum, whose threads find their way down 

 the walls, and give off at the nodes other threads which penetrate the 

 interior of the vesicles. The vesicles further become filled with re- 

 fractive matter, largely obtained from the granules of the pigment epi- 

 thelium, which condenses the mass of the reticulum into the axes of the 

 rods. A portion of this refractive matter exudes through the transverse 

 membrane, where it mixes with the staining matter of the inner limb, 

 and forms the so-called ellipsoid body. 



Cellular Differentiations. || — Prof. M. Heidenhain has taken a 

 critical survey of the differentiations within the cell, discussing 



* Pringsheini's Jahrb. wiss. Bot., xxxiv. (1900) pp. 669-701. Cf. this Journal, 

 1899, p. 476. t Coniptes Rendue, cxxxi. (1900) pp. 1282-4. 



t SB. Akad. Wiss. Wien, cviii. (1899) pp. 449-69 (7 pis. and 1 fig.). 

 § Quart. Joum. Micr. Sci., xliv. (1901) pp. 443-68 (2 pis.). 

 || Anat. Anzeig., xviii. (1900) pp. 513-50 (8 tigs.). 



