. The cell; outlines of general anatomy and physiology. Cells; Anatomy; Physiology; Cells; Anatomy; Physiology. THE VITAL PROPERTIES OF THE CELL 279 cell membranes become dissolved. A connecting bridge, which continually grows broader, develops; after which the proto- plasmic masses stream together from all sides, until the two in- dividuals become transformed into a single large vesicle. The two nuclei, each accompanied by a centrosome, travel towards each other, and place themselves in contact, but, accordiag to Ishikawa, do not fuse (VII. 25). After a time, the conjugating pair of Noctilucr
. The cell; outlines of general anatomy and physiology. Cells; Anatomy; Physiology; Cells; Anatomy; Physiology. THE VITAL PROPERTIES OF THE CELL 279 cell membranes become dissolved. A connecting bridge, which continually grows broader, develops; after which the proto- plasmic masses stream together from all sides, until the two in- dividuals become transformed into a single large vesicle. The two nuclei, each accompanied by a centrosome, travel towards each other, and place themselves in contact, but, accordiag to Ishikawa, do not fuse (VII. 25). After a time, the conjugating pair of Noctilucre again divide into two cells, a partition membrane having developed between them. At the commencement of this division, the pair of nuclei, which have united together, become extended ; they then become constricted in the middle, and divide into two, after which they separate again, the result being that each Noctiluca contains half of each nucleus. Thus the result of conjugation is the production again of two individuals, each of which possesses a nucleus of twofold origin. Fertilisation is followed sooner or later by active multiplication by means of budding and spore formation. The Conjugates (VII. II) are of especial importance in the study of primitive modes of fertilisation. This order is sub- divided into three families : the Desmidiaceas, the Mesocarpese, and the Zygnemaceae. Klebahn (VII. 27) has discovered the minute details of the process of fertilisation in two species of Desmidiacese: the Glos- terium and Cosmarium. Two Glosterium cells, which are shaped somewhat like bent sickles, lie lengthwise against each other, being kept in contact by a gelatinous secretion ; each then develops a protuberance near its centre. The two protuberances come closely into contact and fuse, whilst the wall separating them dissolves, to form a conju- gation canal common to both. Here all the protoplasm from both the conjugating Closterium cells gradually collects, and, detaching itse
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