EXPLANATION OF FIGURES IN PLATE XXVII. 
(To follow page 242.) 
Illustrating Miss Welsford’s paper on Trichodiscus elegans. 
Fig. 1. Mature plant of Trichodiscus elegans , showing the groups of short erect branches in the 
centre of the disc and the hairs towards the periphery, x 70. 
Fig. 2. Part of periphery of disc, showing the free curving branches and the hairs, x 500. 
Fig. 3. A group of short erect branches from the centre of the disc, x 1,000. 
Fig. 4. The lower part of a hair, showing the two basal cells with chloroplasts ; the remaining 
cells contain protoplasm, but no chloroplasts. x 1,000. 
Fig. 5. Part of a young filament, showing branches arising close to the transverse walls, x 1,875. 
Fig. 6. Group of large terminal sporangia from centre of disc. The following stages can be 
seen : one-celled sporangium, two-celled sporangium, eight-celled sporangium, a mature sporangium 
containing zoospores, x 1 ,000. 
Fig. 7. A later stage of the same Two empty sporangia and a sporangium from which the 
zoospores are escaping are shown, x 600. 
Fig. 8. A large intercalary sporangium, showing the pores through which four zoospores have 
already escaped. In the same group two-celled and four-celled sporangia are shown. One of the 
sporangia after dividing into two has set free one of its daughter cells. X 1 ,000. 
F’ig. 9. A zoospore, x 1,000. 
Fig. 10. Two zoospores fusing {from fresh material ). x 1,000. 
Fig. 11. Resting stage of zygote ( from fresh material), x 1,200. 
Fig. 12. Three stages in the fusion of the gametes {front material fixed in Flemming s fluid and 
stained with iron haematoxylin). x 1,200. 
Fig. 13. Stages of germination of the zygote, a , zygote germinating at one end; b , later stage 
of same ; c, zygote germinating at both ends; d, later stage of same, x 1,200. 
Fig. 14. Part of thallus, showing a young plant developed in a sporangium in situ ; four young 
sporangia before division has taken place are also shown, x 750. 
Fig. 15. A seven-celled filamentous plant lying within the wall of the sporangium, which has 
become separated from the plant, x 1,000. 
Fig. 16. A five- celled filamentous plant which has begun to increase in size but is still sur- 
rounded by the sporangium wall, which has become gelatinous, x 1,000. 
Fig. 17. A group of small sporangia, showing empty sporangia and also one which still contains 
four zoospores. x 1,000. 
Fig. 18. A group of aplanospores. x 1,000. 
