ADVANCE IN LOWER PLANT AND ANIMAL FORMS i6i 



PROGRESSIVE ADVANCE IN LOWER PLANT AND ANIMAL FORMS 



Having shown that crystals, plants, and animals have much in common, and that the substances composing 

 them exhibit globular, concentric, radiating, branched, segmented, curved, and spiral arrangements, I have 

 now to point out that the more rudimentary plants and animals are disposed in an ascending series where im- 

 provement in form, structure, and types may be traced. 



The rudimentary plants are seen at Plates iii., iv. The rudimentary and other animals are given at Fig. 9, 

 Plate xii.. Figs. 1 and 2; Plate xvi., Figs 9 and 10; Plate xviii., Fig. 3; Plate xx.. Fig. 1; Plate xxv., 

 Figs. 2, 4, 5, 6, and 7 ; Plate xxvi., Fig. 2 ; Plate xxvii.. Fig. 4 ; Plate xxxv.. Figs. 2, 3, and -5 ; Plate xxxvi.. 

 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.. 

 Figs. 1 and 2. 



The Infusoria, which afford examples of the simplest animals, are alike interesting and instructive, from the 

 fact that they give a clue to the structure of all the higher animals. In these lowly forms, the globular, concentric, 

 radiating, branched, segmented, curved, and spiral arrangements which everywhere obtain in living organisms, 

 and to which attention has been already directed, form a conspicuous feature. These arrangements, which present 

 themselves at the very threshold of existence, are, it appears to me, so important that I devote no fewer than ten 

 plates to their illustration. In these plates the same lettering is employed in the several figures throughout. Thus 

 a, indicates the nucleus or endoplast ; cv, the contractile vesicle or vesicles ; d, the oral aperture ; an, the anal 

 aperture ; /, the flagellum ; and cl, the collar. 



In this connection I have to acknowledge my indebtedness to Mr. W. Saville Kent, from whose interesting 

 and erudite work on the " Infusoria " many of the figures are taken.^ 



It is not necessary to describe the several Infusoria in detail. The plates, and the descriptions thereof, will 

 supply the information I desire to convey. The points I wish especially to establish are the following : — 



L The Infusoria display well-marked globular, concentric, radiating, branched, segmented, curved, and spiral 

 arrangements. 



2. They show a gradual advance in outhne, structure, and function, but no attempt, unless in a general way, 

 has been made at classification. 



3. They display symmetry and asymmetry. 



4. They exhibit centripetal, centrifugal, spiral, and other movements. 



5. They assume a well-marked and distinctive form in the adult condition which, in many cases, they lose 

 during the reproductive process. They advance in the adult state and retrogress and assume the amoebic and 

 shapeless state during transition and the young condition. 



6. They reproduce themselves in several ways ; a, by longitudinal, transverse, and other division ; h, by 

 budding ; c, by swarming ; and d, by reverting to the simple, amorphous, amoebic condition. 



7. They move freely about in the young state, and, not unfrequently, become fixed in the adult state. 



8. They possess pseudopodia, ciha, flagella, tentacles, sensitive filaments, &c., which are under control, and 

 which enable them to secure food, and, if need be, to move from place to place. 



9. They are provided with a nucleus and one or more contractile vesicles ; the latter displaying opening and 

 closing rhythmic movements akin to those occurring in the hearts of vertebrates. 



10. They form colonies, being, in some cases, grouped rosette-fashion and presenting a symmetrical flower-like 

 appearance. 



11. They, in not a few instances, divide, subdivide, and branch hke plants. 



12. They frequently display an elegant cup-shaped collar and an exquisite protecting covering or lorica which 

 render them exceedingly beautiful objects. 



13. They form, in certain cases, the Hving substance of sponges. 



14. They, on many occasions, reveal longitudinal, transverse, spiral, and other marldngs. 



15. They also afi'ord distinct traces of segmentation. 



The globular, concentric, radiating, branched, segmented, curved, spiral, and other arrangements and markings 

 so well seen in the Infusoria are also met with in the pollen, anthers, and other parts of plants connected with 

 reproduction. They are shown at Plate Ixv. 



In this plate all the pecuharities of structure referred to can readily be studied and appreciated. 



Before examining the Infusorial plates it may be useful to describe very briefly one of the typical Zooids, 

 the best for the purpose being the collared monad {Munosiga gracilis). 



1 "A Manual of Infusoria, including a Description of all known Flagellate, Ciliate, andTentaculiferous Protozoa '^^'8«n*l'88f"T™lumes^" 

 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. 



