EVIDENCES OF DESIGN IN REPRODUCTIVE ELEMENTS 155 



PLATE LXI 



Plate Ixi. illustrates globular, concentric, radiating, branched, segmented, curved, and spiral arrangements. 



Fig. 1.— Portion of the epidermis of a salamander in slightly oblique horizontal section, magnified 550 diameters. Cells rounded 

 and polygonal, connected by delicate bridges of protoplasm and containing large nuclei (Wilson), a, Epidermal cells, three of which 

 are undergoing division. The earliest stage of division (spirem) is seen at 6/ a later stage (mitotic figure in the anaphase), showing 

 chromosomes at c; and the final stage (telophase), showing fission of cell-body at d. e, Branched dark pigment-cell which has crept up 

 from lower layers of skin. This figure illustrates circular, pentagonal, and branched arrangements. 



Fig. 2.— Division of the blood-cells in the embryo chick according to Reinak. «, b, c, d, e, Successive stages of division ; /, cell 

 dividing by mitosis. This figure shows concentric and radiating arrangements. 



Pig. 3. — Reticular nucleus («) of the rhizopod {Admosi)ha>riuiii) as figured by Brauer. The reticulation is a form of diff'eren- 

 tiation — the nucleus possessing a complex oi'ganisation. 



Fig. 4. — Low animal form, Amceba proteiui, consisting of a single cell. Magnified 280 diameters (Sedgwick and Wilson). 

 n, Nucleus; wv, water vacuoles ; cv, contracting vacuole ; fv, food vacuole. The amoeba can reproduce itself and move voluntarily in 

 any direction. It reveals traces of difl'erentiation. 



Fig. 5. — Diagram of a cell by Wilson. The basis of the cell consists of a thread-work (iniiome or reticulum) composed of minute 

 granules (microsomes), traversing a transparent ground-substance, a, Nucleus ; a, true nucleolus or plasmosome ; h, chromatin net- 

 work ; c, linin-network ; d, net-knot or karyosome ; e, attraction-sphere containing two centrosomes ; /, /', vacuoles ; g, lifeless bodies 

 (nietaplasm) suspended in cytoplasmic reticulum ; h, plastids lying in cytoplasm. 



This diagram shows that the cell is not, in any sense, a simple homogeneous body. On the contrary, it is differentiated to a 

 considerable extent, a circumstance too frequently overlooked. The cell is originally spherical in form, but becomes indented by 

 growth, crowding, and pressure. 



Fig. 6. — A resting cell {Spurmatogonium) from testis of salamander, showing typical parts (Ravitz). w. Large nucleus bounded by 

 membrane and invested with cytoplasmic thread-work. Contains scattered masses of chromatin and linin-network. a, Attraction 

 sphere with centrosome (/j). The attraction-sphere is a centre of force, and can act either centripetally or centrifugally. 



Fig. 7. — Living branched connective tissue-cell from salamander larva (Fleming). Affords beautiful example of branching 

 arrangement. 



Fig. 8. — Living epidermal cell from larva of salamander in early mitosis (segmented spirem), surrounded by protoplasmic 

 bridges fFleming). Shows concentric, branching, and radiating arrangements. 



FtG. 9. — Living dividing cell of salamander larva. The cell when dividing assumes a dumb-bell shape (Fleming). 



Fig. 10. — Pigment-cell from epidermis of fish (Blennius), as given by Zimmerman, a, Central clear space of aster from which the 

 pigment-granules diverge; n, two nuclei. Shows radiating arrangement to advantage. 



Fig. 11. — Pigment-cell of fish (Sarcjus) showing two nuclei (nn') with aster (»), and rod-shaped central mass (6), according to 

 Zimmerman. Affords good example of branching, radiating arrangements. 



PLATE LXI I 



Plate Ixii. illustrates globular, concentric, radiating, branched, dendritic, curved, and spindle arrangements 

 in the cell. 



Pig. 1. —Leucocyte or wandering cell of the salamander as figured by Heidenhain. The cell contains a large nucleus (n) \yith 

 coarse network of chromatin, two nucleoli («'), and permanent aster (</), with double centrosome at its centre surrounded by attraction- 

 sphere. Illustrates concentric and radiating arrangements. 



Fio. 2. — Same as Fig. 1 — the cell in this case containing two nuclei. 



Fig. 3.— Alveolar or foam-structure of protoplasm in the sea-urchin's egg (Biitachli). a, Aster ; b, attraction-sphere ; c, centrosome. 

 Shows radiating and concentric arrangements in a marked degree. 



Fig. 4.— Branching nucleus from the spinning gland of larva of butterfiy (Pieris), as delineated by Korschelt. It would be 

 difficult to find a better example of branching arrangement in a rudimentary structure. 



Figs. 5, 6, 7, and 8.— Assortment of cells by various investigators showing typical parts. 



Fig. 5.— Spinal ganglion-cell of frog as given by Lenhossek. n, Nucleus ; u, attraction-sphere ; 6, centrosome with several 

 centrioles. 



Fig. 6.— Spermatogonium of frog (Hermann), k, Attraction-sphere (aster), containing a single centrosome (6) ; n, nucleus with 

 single plasmosome (c) and net-knots (rf). 



Fig. 7.— Peritoneal epithelium from larva of salamander (Fleming). ii, Large reticulated nucleus with net-knots (nk) ; b, two 

 centrosomes. 



