Picture - Cosmic Polymath

EVIDENCES OF DESIGN IN REPRODUCTIVE ELEMENTS 159
PLATE LXIII (continued)
Fig. 10.— Fertilisation in the plant (Pilularia) as delineated by Campbell.
A, B. Early stages in the formation of the spermatozoid.
C. The mature spermatozoid. The nucleus lies in the spiral turns of the latter at n, a cytoplasmic mass containing starch
corpuscles being seen at s.
D. Archegonium during fertilisation. In the centre, the ovum (o)
concentric, segmented, and spiral arrangements.
contains the apposed germ nuclei (g, n). Shows spherical,
Fig. 11.—Spermatogonium of Salamander as figured by Driiner. n, Nucleus; a, enormous aster, its rays giving indications of
nine concentric circles of microsomes ; c, centrosome, or centre of force, from which the rays of the astei- diverge, and round which
the circles ot microsomes arrange themselves. Affords an outstanding example of radiating and concentric ariangenients.
Fig. 12.— Germinal cells of Volvox as figured by Overton.
A. Spermatozoid. cv, Contractile vacuoles ; e, eye spot (chromoplastid) ; p, pyrenoid.
B. Spermatozoid stained to show nucleus (n).
C. Ovum (oosphere) with large central nucleus (n), and peripheral layer of ehroniatnphores. p, Pyrenoid. Shows spherical,
concentric, and branching arrangements.
Figs. 13 and 14.—Germinal \'esicles of eggs, showing chromosomes, tetrads, and nucleoli.
Fig. 13. Cyclops xtrenunx, illiistrating Hacker's account of the tetrad formation from elongated doulile rods with group of
accessory nucleoli (Hacker).
Fig. 14.—Germinal vesicle of an annelid (Ophryotrocha), showing nucleolus («'), four chromosomes (c, r, c, c), and asters (a, a'),
according to Korschelt. Shows spherical, concentric, and radiating arrangements.
Fig. 15.—Living ovarian egg of an insect, water-beetle (Dytiscus), iV} figured by Korschelt. The egg {ov) lies between two
groups of nutritive cells ;
the germinal vesicle sending amo'boid processes into the dark mass of food-granules.
Fig. 16.—Egg and nurse-cell of the annelid (Ophryotrocha) in the young stage, as depicted by Korschelt. In this condition the
nurse-cell (m) is considerably larger than the egg (o). As the ovum grows the egg becomes larger and the nurse-cell smaller—the
latter ultimately shrivelling up. The egg practically lives on the nurse-cell so long as it lasts.
Fig. 17.—Mitosis in the flagellate (Noctiluca), early prophase (Ishikawa). n, Nucleus ; s, attraction-sphere ; c, two centrosomes.
PLATE LXIV
Plate Ixiv. illustrates globular, radiating, concentric, branched, segmented, and spiral arrangements, especially
the latter (spiral) in the sexual elements.
Fig. 1.—Spermatozoids of plants. A to D as given by Guignard, and E to F as given by Strasburger.
A. Of an alga (Fucus) ; B. Liverwort (Pellia) ; C. Moss (Sphagnum) ; D. Fern (Angiopteris) ; E. Marsilia ; F. Fern (Phegopteris).
In A, a red chromatophore occurs at the right of the nucleus, and at F, the nucleus is coloured dark. Illustrates spiral, branching,
and spherical arrangements.
Fig. 2.—Unusual form of spermatozoa.
A, B, C. Living amceboid spermatozoa of the Crustacean (Polyphemus), as figured by Zacharias. D, E. Spermatozoa of crab
(Dromia); F, of Ethusa; G, of Maja ; and H, of Inachus as given by Grobben. I, of Lobster (J?oma)-K.