Il6 EISEN. [Vol. XVII. 



dently forming a casing to the granules. The beading of the contractile fibers 

 is probably of the same nature and origin as the mid-body. That is, the beads 

 may serve as storage reserves of plasma to be used when the contractile fiber is 

 lengthened or shortened. When suddenly lengthened on account of strain the 

 plasma is probably supplied by the beads, and vice versa ; when the contractile 

 fiber requires to be suddenly shortened its superfluous plasma is quickly accumu- 

 lated in the beads. Chromioles are plainly visible in the chromosomes, especially 

 in the one to the left. Zeiss Apo. 2 mm., Apert. i, 40, Oc. 18. 



Fig. 113. Auxocyte. Detail figure of an archosome and six of its contractile 

 fibers, showing them to start from the outer edge of the centrosphere. Some of 

 the fibers connect with the inner centriole by a fine bar of somosphere. The 

 contractile fibers are strongly beaded, somewhat of the nature of a muscle fiber. 

 The beads are situated in zigzag fashion and covered by a sheathing of fibrous 

 nature. There are three strongly stained accessory archosomes at the pole. The 

 chromosomes are only indicated. The figure is drawn to a larger scale. 



Fig. 114. Spermatocyte. Detail figure of a fiber cone showing the connection 

 of the fibers with the accessory archosomes. Several of the latter possess amoe- 

 boid centrospheres. The nucleus is in the checkerboard stage. 



Fig. 115. Spermatocyte. Detail figure of a fiber cone. The outer edge of 

 the cone forms also the outer cell wall. An accessory archosome with several 

 centrioles is near the apex of the cone. This cone is less advanced in dissolu- 

 tion than the one figured in Fig. 114, though it is from the same cell. 



Fig. 1x6. Spermatocyte. Detail figure of a fiber cone in dissolution, showing 

 the granulated and beaded structure of the fibers. At the apex is an accessory 

 archosome. The outer edge of the cone is closely pressed against the cell wall. 



Fig. 117. Spermatocyte. Detail of a fiber cone in dissolution. The accessory 

 archosomes have left the apex of the cone and are now congregating around the 

 reconstituting granosphere. Each centrosome possesses an amoeboid centro- 

 sphere. Some of the centrosomes are yet attached to the cone fibers. The outer 

 lining is the cell wall. 



Fig. 118. Spermatocyte. A nucleus in the chrysanthemum stage, showing 

 the staple-shaped chromosomes in a stage of growth. The nuclear membrane is 

 formed in the immediate vicinity of the chromosomes. The chromomeres and 

 some of the chromioles are distinct. The linin network is stained red. 



Fig. 119. Spermatocyte. A nucleus and two detail figures of chromosomes. 

 The details are drawn on a slightly larger scale, but with the same magnification 

 and objective. The chromosomes are further advanced than in Fig. 118. The 

 chromomeres are separating. Some of them contain eight or ten, others only 

 three to four chromioles. 



Fig. 120. The homoeotypic mitosis by equation division of the spermatocyte 

 from the perfectly split V to the confluent umbrella stage, a to /"show the V- 

 shaped chromosomes as they are thrown on the central spindle; some are seen in 

 front view, others in side view. The fibers connecting with the chromosomes are 

 contractile fibers, g to h show the chromosomes in the act of separation, being 

 pulled apart by the contractile fibers. At / is seen one of the daughter-chromo- 

 somes in which the chromioles are very distinct, i to k, chromosomes after the 

 halves have separated and the daughter-chromosomes have formed. /, m, 

 chromosomes in the confluent umbrella stage ; in / no endochromatic granules 

 are seen on account of too dense staining. In vi many endochromatic granules. 



