430 r. W. GAMBLE AND FREDERICK KEEBLE. 



Fig. S.— a very young Convoluta (0"157 mm. in length when contracted), 

 to show the development of the " green cells." The specimen was hatched 

 in sea water, August 21st, l'J02, and placed in the open from that day till 

 August 23rd. It was tiien drawn. The eyes {OC.) had developed, and 

 colourless, yellow, and green cells were present. The figure shows the distinct 

 leucoplasts, the pyrenoid, the gradual development of chlorophyll and of the 

 stigma. On testing for starch a colourless and yellow cell gave a distinct 

 reaction {J. B.). 



Fig. 9. — A specimen (0"35 mm. long, somewhat contracted) taken on the 

 shore at Tregastel, September 5th, 1902, and drawn to show the numerous 

 diatom frustules {Biat. and R.) with which its gut was filled. The figure is 

 typical of many Convoluta 3—4' mm. long. It sliows that the previous 

 view maintained by Ilaberlaudt and Georgevitch of the abstinence of Convo- 

 luta from solid food is incorrect. 



Figs. 10 and 11. — Remains of diatoms from a specimen of Convoluta 

 4"S6 mm. long, full-grown but immature. In Fig. 10 the remains are hardly 

 recognisable. 



Fig. 12. — A specimen 042 mm. long, hatched in sea water, and drawn a 

 few hours after hatching. The fat is still present in the otocyst. The eyes 

 have developed exceptionally rapidly. Fat is still abundant in the peripheral 

 parenchyma. In the gut a large phagocyte (PIIJG.) contains several 

 developing " green cells " in the colourless early stage. These colourless 

 cells vary in the size and nature of their contents. The largest cell is 

 0"012 mm. in greatest width, the smallest is 0'006 mm. The contents are 

 either mere globules of fat or ciirved and yellowish leucoplasts in which 

 chlorophyll is just developing. The glands (Gl.) are indicated. 



Fig. 13. — A specimen hatched in sea water and drawn the following day 

 (September 12lli, 1902). A group of five developing "green cells" are 

 shown with the chloroplasts already established. 



Fig. 14. — A specimen hatched in sterilised water and drawn a few hours 

 afterwards. Two developing green cells are shown. One {C. G. C), enclosed 

 in a multinucleate phagocyte (PHAG.), contains several peripheral leucoplasts ; 

 the other, also enclosed in a wandering cell, shows the excentric nucleus but 

 no distinct leucoplast. 



Fig. 15. — A specimen of Convoluta roscoffensis a week after hatching 

 in sea water. Only three green cells are present {G. C). The figure shows 

 the mouth {Mo.), the nucleated phagocyte that guards it (PIUG.), the 

 central parenchyma or gut now free from fat, the peripheral parenchyma in 

 which fat is still abundant streaming inwards and outwards as the musculature 

 constrains it. 



Fig. 16. — This specimen hatched from a capsule placed in water sterilised 

 at 60° C, and placed in darkness on August 18th, 1902. On August 28th 

 the Convoluta, being then presumably about three days old, was put in the 



