ZOOLOaY AND BOTANY, MICROSCOPY, ETC. 317 



element), and small peripheral smooth cells applied to their surface 

 (male element), which he considered to be primordial ovules sur- 

 rounded with epithelial cells, and consequently as young male 

 Graafian follicles, are the primitive spermatospore covered with the 

 protospermoblasts, and the group of daughter-cells, which, according 

 to Balbiani, are produced by budding of the epithelial cells, are in 

 fact the deutospermoblasts. 



There is therefore no necessity to imagine the intervention of a 

 conjugation of elements of supposed different sexuality, and a fecunda- 

 tion of which there is no serious proof. 



Further researches on the Plagiostomi (Maja and ScylUum) and 

 Amphibia (JRana, Hyla, and Bufo), have confirmed the author's views. 

 He is also satisfied that the oval refracting bodies observed on the sides 

 of the bundles of spermatozoids before maturity (the " problematical 

 bodies " of Semper to which Balbiani attributed a very important 

 function as the female fecundating element) are simply nuclei of 

 deutospermoblasts which have not undergone division. 



Cell-structure.* — The first portion of W. Flemming's third con- 

 tribution to this subject deals with the ovum of the Echinodermata. 

 He finds that in the rij)e ovarian ovum of the Echinoidea (and it may 

 be supposed in others also), there is a radiate arrangement of the 

 protoplasm of the eggs, which persists and even becomes more distinct 

 during fertilization ; this radiation is not to be confused with the 

 formation of the asters. There exists a sperm-nucleus which fuses 

 with the ovarian nucleus ; the sperm-nucleus is formed by the anterior 

 portion of the head of the spermatozoon, or that part to which 

 Flemming gives the name of the chromatic substance. The doctrine 

 of Fol, that the protoplasm of the male element alone enters into 

 union, cannot be held ; what is rather true is that the chromatin (or 

 nuclear body), both of the male and of the female nucleus, enters into 

 the formation of the cleavage-nucleus. The division of this last, 

 formed, as we have seen, by copulation, differs in no essential respect 

 from the karyokinetic (indirect) division of other cell-nuclei. All 

 the filamentar forms, with unimportant changes in certain phases, are 

 exactly similar to those already noted when describing the division of 

 the nuclei of the cells of tissue. The mother-star of the karyokinetic 

 figure has not the same centre as the radial arrangement of the ovarian 

 protoplasm. The radial forms of the daughter-nuclei have, however, 

 the same centre ; but this is true also of other than ovarian cells. 



The author insists on the fact that most ova are very unsuitable 

 objects for the study of dividing nuclei ; the observations by him on 

 this subject were carried out at Naples on Sphcerecliinus hrevhpinosus, 

 Echinus miliaris, and Toxopneustes lividus. 



Dealing with the phenomena of nucleus-division in the walls of 

 the embryo-sac of Lilium and other plants, Flemming directs attention 

 to the results of Strasburger, from which his own dilfcr considerably. 

 He finds that in all nuclear figures there are many more chromatic 

 filaments than that author has represented, and that these do not 



♦ Arch. Mikr. Anat., xx. (1881) pp. 1-87 (4 pl.-i.). 



