192 PERCY SLADEN TRUST EXPEDITION. 
EXPLANATION OF THE PLATES. 
All the figures from photographs about } natural size. 
PLATE 19. 
Lithophyllum Gardineri, Fosl., f. typica. 
Figs. 1-3. Specimens from Salomon Atoll, Chagos. 
Fig. 4. A rather young specimen attached to a fragment of a decaying root: Coetivy. 
Lithophyllum Gardineri, Fosl., f. obpyramidata, 
Fig. 5. A specimen forming a transition to the typical form: Salomon Atoll, Chagos. 
Figs. 6,8. Specimens with much anastomosing and in part rather delicate branches: Egmont Atoll 
Chagos. 
Vig. 7, Aspecimen seen from below, with the outer branches partly rather dilated at their ends : Coetivy. 
2) 
PuatTe 20. 
Lithophyllum Gardineri, Fosl., f. subhemispherica. 
Part of the alga seen from above : Egmont Atoll, Chagos. 
{ Reprinted from ‘ Transactions of the Linnean Society of London,’ ser. 2, Botany, vol. vii. (1907) 
pp- 93-108, plates 15 and 16, as indicated by the pagination at the foot of each page. ] 
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