XIII.
| FIG. | |||
| 1. | Grantia compressa | 14. | Vorticella nebulifera |
| 2. | Euglena viridis | 15. | Zoothamnium arbuscula |
| 3. | Dinobryon sertularia | 16. | Do. do. contracted |
| 4. | Synura uvella | 17. | Vaginicola crystallina |
| 5. | Peridinium tabulatum | 18. | Ophrydium versatile (colony) |
| 6. | Coleps hirtus | 19. | Do. do. (single zoöid) |
| 7. | Trachelocerca viridis | 20. | Cothurnia imberbis |
| 8. | Trachelius ovum | 21. | Pyxicola affinis |
| 9. | Amphileptus gigas | 22–23. | Stylonychia mytilus |
| 10. | Bursaria Mülleri | 24. | Acineta grandis |
| 11. | Folliculina elegans | 25. | Loxophyllum meleagris |
| 12. | Stentor polymorphus | 26. | Euplotes charon (dividing) |
| 13. | Trichodina pediculus | 27. | Chætonotus larus |
XIII.
The inhabitants of these shells are Amœbæ, mere masses of jelly, and some forms may be found sliding over the weeds in almost every rock-pool. The anchor-mud, already spoken of, always contains some, and many forms may be found in the sand from sponges, which should be passed through a series of wire sieves, of increasing fineness, and the residuum in each case be examined dry under a one-inch power. The shells may be picked up with a needle which has been slightly greased by being passed over the hair, and they may be mounted by sticking them to the slide with thin starch paste, putting on a cover-glass properly supported, and then running turpentine under the cover-glass, heating to expel the air, and finally filling up with balsam. Or, as opaque objects, they may be mounted in a cell dry. The forms are endless, but all are beautiful, and a few examples are given in Plate IX. Fig. [4] (Miliolína), and Plate XII. Fig. [7], which is a portion of the shell to show the holes, Fig. [13] (Polystomella), Fig. [14] (Truncatulína), Fig. [15] (Polymorphína), Fig. [16] (Miliolína, partly fossilised), Fig. [18] (Lagéna). and Fig. [20] (Biloculína).
Allied to these are the lovely Radiolaria, whose shells, constructed on a similar plan, are composed of flint. They are found in remarkable profusion in the deposit from Cambridge, Barbados, but also in a living state at even enormous depths in the ocean. The present writer has obtained many forms from Challenger soundings, and the great authority on this subject is Haeckel’s report in the official accounts of the expedition of the above-named vessel.
The Hydroid Zoophytes are represented by several examples. These creatures are soft and almost gelatinous, and are furnished with tentacles or lobes by which they can catch and retain their prey. In order to support their tender structure they are endowed with a horny skeleton, sometimes outside and sometimes inside them, which is called the polypidom. They are very common on our coasts, where they may be found thrown on the shore, or may be dredged up from the deeper portions of the sea.
Fig. [13] is a portion of one of the commonest genera, Sertularia, showing one of the inhabitants projecting its tentacles from its domicile. Fig. [15] is the same species, given to show the egg-cells. This, as well as other zoophytes, is generally classed among the sea-weeds in the shops that throng all watering-places.