_Fig._ 1. Arachnoidiscus--2. Actinocyclus (Bermuda)--3. Cocconeis (Algoa Bay)--4. Coccinodiscus (Bermuda)--5. Isthmia enervis--6. Zygoceros rhombus--7. Campilodiscus clypeus--8. Biddulphia--9. Gallionella sulcata--10. Triceratium, found in Thames mud--11. Gomphonema geminatum, with their stalk-like attachments--12. Dictyocha fibula--13. Eunotia--14. Cocconema--15. Fragilaria pectinalis--16. Meridion circulare--17. Diatoma flocculosum. PLATE XII.--_Page_ 438. MICRO-PHOTOGRAPH OF TEST DIATOMS. Taken with Zeiss’s 3 mm. N.A. 1·40 by Mr. A. A. Carvell for the Author. _Fig._ 1. Portion of Surirella gemma, magnified × 1,000--2. Broken Frustule of Pleurosigma angulatum, × 750--3 and 5. Triceratium favus ×--1,000--4. Navicula rhomboides × 1,300--6. Pleurosigma formosum, showing black dots--7. P. formosum, showing white dots, × 750. PLATE XIII.--_Page_ 454. PHANEROGAMIÆ--ELEMENTARY TISSUE OF PLANTS. _Fig._ 1. Elementary ovid cells--2. Branching tissue--2A and 3. Spiral vessels from Opuntia vulgaris--4. Stellate tissue, section of rush--5. Mushroom spawn--6. Starch from _Tous-les-mois_--7. Starch from sago--8. Starch from rice--9. Wheat-starch--10. Rhubarb starch in isolated cells--11. Maize-starch--12. Oat-starch--13. Barley-starch--14. Section of Potato cells, filled with healthy starch--15. Potato starch more highly magnified--16. Section of Potato with nearly all starch absent--17. Potato with starch destroyed by fungoid disease--18. Ciliated spermagones--19. Hairs of stinging-nettle--20. Section of cellular parenchyma of ripe strawberry. PLATE XIV.--_Page_ 472. STELLATE AND CRYSTALLINE TISSUE. _Fig._ 1. Epidermis of husk of wheat, spiral vessels and silicious crystals--2. Section of cane, silicious cell walls, internal portion filled with granular bodies--3. Cuticular layer of the onion, showing crystals of calcium carbonate and oxalate--4. Cells of garden rhubarb, with crystalline bodies and raphides--4_a_. Another layer filled with starch grains--5. Section of pear, testa, sclerogenous and granular tissue--6. Stellate hairs, sinuous cells and silicious parenchyma of leaf of Deutzia scabra, under surface--7. Silicious cuticle layer of grass, Pharus cristatus. PLATE XV.--_Page_ 482. RHIZOPODA.--GROMIA.--FORAMINIFERA. _Fig._ 1. Astrorhiza limicola--2. Lieberkühnia paludosa--3. Micro-gromia socialis undergoing fission--4. A colony of Hertwig’s Micro-gromia socialis--5. G. Lieberkühnia--6. Egg-shaped Gromia, G. oviformis, with pseudopodia extended, magnified 500 diameters. “Hertwig Ueber Micro-gromia, archiv. für Mickr. Anat. bdx.” PLATE XVI.--_Page_ 510. SPONGE SPICULES.