EXPLANATION OF PLATE 29

Transcription

1 THE CILIABY MECHANISMS OF LAMELLIBEANCHS 435 Studnitz, G., "Morphol. und Anat. von Lima inflata, nebst biolog. Unterauch. an Lima hians", 'Zool. Jahrbiicher', Bd. liii. Thiele, J., "Mollusca", in Kukenthal, 'Handbuch der Zoologie', Bd. v, Berlin. Wallengren, H., "Biologie der Muscheln. I. Die Wasserstromungen", 'Lunds Univ. Arsskrift', N.F., Afd. 2, Bd. i, nr. 2. Watson, H., "Anatomy and Affinities of Plicatula", 'Proc. Malac. Soc, Lond.', vol. xix, pt. 1. Willey, A., 1911.' 'Convergence in Evolution.' London. Winckworth, R., "Nucula nitida", 'Proc. Malac. Soc, Lond.', vol. xix, pt "British Marine Mollusca", ' Journ. Conch.', vol. xix, no ^ "Names of British Mollusca II", ibid., vol. xx, no a. "Names of British Mollusca III", ibid., vol. xx, no. 2. Woodward, M. F., "Anatomy of Pleurotomaria beyrichii", 'Quart. Journ. Micr. Sci.', vol. xliv, Worley, L. G., "Dual nature of metachronism in ciliated epithelium", 'Journ. Exp. Zool.', vol. lxix. Yonge, C. M., "Structure and Physiology of Organs of Feeding and Digestion in Ostrea edulis", 'Journ. Mar. Biol. Assoc.', vol. xiv, N.S., " Structure and Function of Organs of Feeding and Digestion in Septibranchs, Cuspidaria and Poromya", 'Phil. Trans. Roy. Soc, Lond.', B, vol. ccxvi "Feeding and Digestion in Pterocera and Vermetus... Crystalline Style in Gastropoda." Great Barrier Reef Expd , 'Sci. Repts.', vol. i, no. 10. Brit. Mus. (Nat. Hist.) "Digestion in Ciliary Feeding Animals", 'Journ. Mar. Biol. Assoc.', vol. xx, N.S 'Mode of Life, Feeding, Digestion and Symbiosis with Zooxanthellae in Tridacnidae.' Great Barrier Reef Expd Brit. Mus. (Nat. Hist.), vol. i, no a. -"Evolution of Swimming Habit in Lamellibranchia", 'Mem. Mus. Roy. Hist. Nat. Belg.', ser. 2, fasc " Biology of Aporrhais pes-pelecani and A. serresiana", 'Journ. Mar. Biol. Assoc.', vol. xxi, N.S. Zittel, K. A. von, 'Text-book of Palaeontology.' English edition edited by C. R. Eastman, vol. 1, 2nd edition. Macmillan & Co., Ltd. (reprinted in 1927 and 1937) EXPLANATION OF PLATE 29 Fig. 1. Lima hians. Transverse section of a plica to show vestiges of ciliary interfilamentar junctions (i.e.), ciliary junction between two limbs of a plica (c.j.), and muscle fibres, o./., apical filament; ch., darkly staining chitin; h.m., horizontal muscle-fibres of interfilamentar junctions;

2 436 D. ATKINS h.m.p.f., horizontal muscle-fibres of principal filaments; i.l.s., interlamellar septum; m.g., mucous gland; p.ch., pale-staining chitin; p.f., principal filament; v.n., vertical nerve. Bouin-Duboscq's fixative; iron haematoxylin and acid fuehsin. X 344. Kg. 2. Pinna fragilis. Transverse section of three filaments, showing micro-latero-frontal cilia (mi-l-fx.) and vestiges of ciliary interfilamentar junctions (i.e.). ch., chitin; /.c, frontal cilia; h.m., horizontal muscle-fibres; I.e., lateral cilia; p.ch., pale-staining chitin. Bouin-Duboscq's fixative; iron haematoxylin and acid fuehsin. X ca Fig. 3. Transverse section of junction between dorsal edges of ascending lamellae of two inner demibranchs. A, Placuna placenta (?). The union is mostly organic but with a short ciliary junction ventrally. B, Isognomon alata. The junction is mostly ciliary but with a short organic union ventrally. c.j., ciliary junction; ch.s., chitinous supporting structure; i.e., interlocking cilia; l.m., longitudinal muscle; n., nerve; t.m., transverse muscle-fibres. Alcohol fixation; iron haematoxylin and acid fuehsin. X ca. 56.

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4 GKASSHOPPEB EGG 457 Needham, J., 'Chemical Embryology.' Cambridge. Reaumur, R. A. F. de, 'Memoires pour servir a l'histoire des inseetes', 'Histoire des fourmis.' New York and London. Roonwal, M. L., "Fate of embryonic membranes in insects", 'Current Sci.', "Growth-changes and structure of the egg of Locusta migratoria migratorioides", 'Bull. Ent. Res.', 27. Slifer, E. H., "Insect development. IV. External morph. of grasshopper embryos", 'Journ. Morph.', "Origin and fate of the membranes surrounding the grasshopper egg", 'Quart. Journ. Mier. Sci.', 79. Slifer, E. H., and King, R. L., "Grasshopper eggs and the paraffin method", 'Science', 78. Uvarov, B. P., "Insects and climate", 'Trans. Entomol. Soc. London', 78. Weber, H., " Lebensweise und Umweltbeziehungen von Trialeurodes vaporariorum", 'Zeit. Morph. Okol. Tiere', 23. EXPLANATION OF PLATE 30. Fig. 1. Longitudinal section through the posterior tip of a Melanoplus differentialis egg which has been kept at 25 C. for the three days since it was laid. The serosa («.) and germ-band or embryo (e.) lie directly beneath the chorion (ch.) and at the surface of the yolk (y.). A fragment of a micropyle is visible in the chorion in the upper left-hand corner of the drawing. X160. Fig. 2. Diagrammatic, lateral view of an egg, from which the chorion has been removed, to show the size of the hydropyle at the posterior end of the egg. The concave side of the egg represents the ventral surface. XlO. Fig. 3. Diagrammatic view of an egg, from which the chorion has been removed, as seen from the posterior end. X 10. Fig. 4. A section through the hydropyle at right angles to the surface of an egg fixed twelve days before hatching was due. Note the striated appearance of the modified yellow cuticle as seen under high magnification, x 1,678. Fig. 5. A section through a part of the hydropyle and a few of the hydropyle cells cut at right angles to the surface of an egg fixed twelve days before hatching was due. X 680. Fig. 6. Longitudinal section through the tip of an egg fixed shortly before blastokinesis (Text-fig. 1 A represents an egg at this same stage). The serosa (s.) has withdrawn from the white cuticle (we.) leaving a liquidfilled space between the two. A few particles of yolk are enclosed within the serosa. m., fragment of micropyle; ch., chorion; ye., yellow cuticle; h., hydropyle; he., hydropyle cells. X160.

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6 478 CATHERINE HAYES Taylor, Monica, "Nuclear Divisions in Amoeba proteus", 'Quart. Journ. Micr. Sci.\ "Amoeba proteus: some new Observations on its Nucleus, Life-History, and Culture", ibid., "Development of the Nucleus of Amoeba proteus, Pallas (Leidy). (= Chaos diffluens (Schaeffer) )", ibid., 71. EXPLANATION OP PLATES 31 AND 32. LETTERING. N., nucleus; c.b., chromatin blocks of the nucleus; C.V., contractile vacuole; F. V., food vacuole (the organism being a large encysted Flagellate); F.r., food vacuole (small Flagellates); s.c, cubic crystal; c, dipyramidal or oval crystal; N.S., nutritive spheres; k., karyosome; n.m., nuclear membrane; n.sp., nuclear sap; n.s., nutritive sphere; ch., chromatin in the karyosome. PLATE I. Fig. 1. Free-hand drawing (not to scale) made from a large, living adult Amoeba discoides. PLATE II. All the figures were drawn from specimens fixed in Bouin's fluid and stained in Ehrlich's haematoxylin. Camera lucida with a No. 5. compens.- ocular and a Zeiss Apochromat. 2 mm. oil immersion objective. Figs. 2, 3, and 4 represent resting nuclei; the karyosome of 2 is seen in 'plan'; of 3 in 'elevation', and of 4 pushed to one side of the nucleus. Figs. 5 and 6 early stages of division of the nucleus. Fig. 7. Nucleus dividing and bent into afigureof eight shape. Fig. 8. Division of the nucleus almost complete, half the karyosome passing into each daughter nucleus. Figs. 9 and 10. The nuclear division is completed, but the daughter nuclei have not separated. Fig. 11. Three nuclei from one amoeba. Cytoplasmic division has not kept pace with nuclear division for one of the daughter nuclei of the first division has already divided. Fig. 12. A nucleus with no trace of a nuclear membrane. Fig. 13. Small portion of an amoeba an agamont showing nucleus without nuclear membrane; a, agametes and n.s., ordinary nutritive spheres. Fig. 14. Encysted agametes, a-g, after disintegration of the agamont. Fig. 15. A young Amoeba discoides.

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8 Quart. Journ. Micr. Sci. Vol. 80, N. S., PL Scale of figs.13-15