Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
ADVANCE IN LOWER PLANT AND ANIMAL FORMS i6i<br />
PROGRESSIVE ADVANCE IN LOWER PLANT AND ANIMAL FORMS<br />
Having shown that crystals, plants, and animals have much in common, and that the substances composing<br />
them exhibit globular, concentric, radiating, branched, segmented, curved, and spiral arrangements, I have<br />
now to point out that the more rudimentary plants and animals are disposed in an ascending series where improvement<br />
in form, structure, and types may be traced.<br />
The rudimentary plants are seen at Plates iii., iv. The rudimentary and other animals are given at Fig. 9,<br />
Plate xii.. Figs. 1 and 2; Plate xvi., Figs 9 and 10; Plate xviii., Fig. 3; Plate xx.. Fig. 1; Plate xxv.,<br />
Figs. 2, 4, 5, 6, and 7 ; Plate xxvi., Fig. 2 ; Plate xxvii.. Fig. 4 ; Plate xxxv.. Figs. 2, 3, and -5 ; Plate xxxvi..<br />
Figs 1, 3, and 4 ; Plate xxxvii. ; Plate xli. ; Plate xlii.. Figs 3 and 4 ; Plate xliii., Figs 2, 3, 5, and 6 ; Plate xlvi..<br />
Figs. 1 and 2.<br />
The Infusoria, which afford examples of the simplest animals, are alike interesting and instructive, from the<br />
fact that they give a clue to the structure of all the higher animals. In these lowly forms, the globular, concentric,<br />
radiating, branched, segmented, curved, and spiral arrangements which everywhere obtain in living organisms,<br />
and to which attention has been already directed, form a conspicuous feature. These arrangements, which present<br />
themselves at the very threshold of existence, are, it appears to me, so important that I devote no fewer than ten<br />
plates to their illustration. In these plates the same lettering is employed in the several figures throughout. Thus<br />
a, indicates the nucleus or endoplast ; cv, the contractile vesicle or vesicles ; d, the oral aperture ; an, the anal<br />
aperture ; /, the flagellum ; and cl, the collar.<br />
In this connection I have to acknowledge my indebtedness to Mr. W. Saville Kent, from whose interesting<br />
and erudite work on the " Infusoria " many of the figures are taken.^<br />
It is not necessary to describe the several Infusoria in detail. The plates, and the descriptions thereof, will<br />
supply the information I desire to convey. The points I wish especially to establish are the following —<br />
:<br />
L The Infusoria display well-marked globular, concentric, radiating, branched, segmented, curved, and spiral<br />
arrangements.<br />
2. They show a gradual advance in outhne, structure, and function, but no attempt, unless in a general way,<br />
has been made at classification.<br />
3. They display symmetry and asymmetry.<br />
4. They exhibit centripetal, centrifugal, spiral, and other movements.<br />
5. They assume a well-marked and distinctive form in the adult condition which, in many cases, they lose<br />
during the reproductive process. They advance in the adult state and retrogress and assume the amoebic and<br />
shapeless state during transition and the young condition.<br />
6. They reproduce themselves in several ways ; a, by longitudinal, transverse, and other division h, by<br />
;<br />
budding ; c, by swarming ; and d, by reverting to the simple, amorphous, amoebic condition.<br />
7. They move freely about in the young state, and, not unfrequently, become fixed in the adult state.<br />
8. They possess pseudopodia, ciha, flagella, tentacles, sensitive filaments, &c., which are under control, and<br />
which enable them to secure food, and, if need be, to move from place to place.<br />
9. They are provided with a nucleus and one or more contractile vesicles ; the latter displaying opening and<br />
closing rhythmic movements akin to those occurring in the hearts of vertebrates.<br />
10. They form colonies, being, in some cases, grouped rosette-fashion and presenting a symmetrical flower-like<br />
appearance.<br />
11. They, in not a few instances, divide, subdivide, and branch hke plants.<br />
12. They frequently display an elegant cup-shaped collar and an exquisite protecting covering or lorica which<br />
render them exceedingly beautiful objects.<br />
13. They form, in certain cases, the Hving substance of sponges.<br />
14. They, on many occasions, reveal longitudinal, transverse, spiral, and other marldngs.<br />
15. They also afi'ord distinct traces of segmentation.<br />
The globular, concentric, radiating, branched, segmented, curved, spiral, and other arrangements and markings<br />
so well seen in the Infusoria are also met with in the pollen, anthers, and other parts of plants connected with<br />
reproduction. They are shown at Plate Ixv.<br />
In this plate all the pecuharities of structure referred to can readily be studied and appreciated.<br />
Before examining the Infusorial plates it may be useful to describe very briefly one of the typical Zooids,<br />
the best for the purpose being the collared monad {Munosiga gracilis).<br />
1 "A Manual of Infusoria, including a Description of all known Flagellate, Ciliate, andTentaculiferous Protozoa<br />
'^^'8«n*l'88f"Tlumes^"<br />
Account of the Organisation and Ailinitfes of the Sponges," by W. Saville Kent, F.I„S., F.Z.S., F.R.M.S., &c. London, 1880-1882. 3 volumes.