76 Proceedings of the Royal Physical Society. 
SOMATIC MITOSIS. 
Dividing somatic nuclei, though rare, can be found in muscle and gland 
cells. An attempt to obtain an abundant supply of mitotic figures by cutting 
sections of developing eges was not very successful. The small size of the 
nuclei and the large amount of yolk globules, coupled with the technical 
difficulties of sectioning eggs with thick chitinous coats, rendered the results 
unsafe as regards reliable cytological detail. 
In the prophase (Fig. 36) it is possible to count twenty-four chromosomes, 
some of which are exceedingly small. The same massing of the chromosomes 
towards the centre of the cell, already described, succeeds the disappearance 
of the nuclear membrane. A perfectly typical spindle is organised (Fig. 37), 
the spindle fibres being best fixed in Gilson-Petrunkewitsch. The late 
telophase (Fig. 38) reveals the same tendency of the chromosomes to pair 
as was seen in the spermatogonial telophases, 7.e. not more than twelve 
radiating processes emerge from the telophasic mass. 
SUMMARY. 
1. The number of chromosomes in Fasciola hepatica is twenty-four in the 
diploid and twelve in the haploid number. 
bo 
Cells which have undergone the penultimate spermatogonial division 
are grouped in masses of four. 
In late telophase of the penultimate spermatogonial division indications 
Oo 
of a pairing of chromosomes can be detected. 
4. Cells which have undergone the last spermatogonial division are grouped 
in masses of eight. 
Or 
In telophase of the last spermatogonial division the twenty-four chromo- 
somes pair into twelve. , 
6. In the late telophase of the somatic mitoses there is a tendency of the 
chromosomes to emerge in pairs from the telophasic chromatin mass. 
EXPLANATION OF PLATES III. ann IV. 
All figures, except 9, 10, 15, 22, were drawn with the Abbé camera under Leitz +, oil- 
immersion objective, and Zeiss compensating ocular 12, giving a magnification as 
reproduced of 2200 diameters. 
Figs, 9, 10, 15, 22 are drawn to a magnification of 1270. 
[ ConTRACcTIONS:—F'= Flemming fixation: S—Spermatogonial. | 
Figs Resting nucleus. 8S. (Gil.-Pet.) 
Lee e De Very early prophase. S. (F.) 
Figs. 3-5. Prophases. 8S. (F.) 
fg. ~ 6: Metaphase. S. (F.) 
Figs. 7,8. Telophases.. S. (F.) 
