626 



SUPPLEMENT 



We proceed to give Mullet's scientific ar- 

 rangement of the infusoria, connecting with 

 each genus the individual selected for illustra- 

 tion of special character. 



I. THOSE WANTING EXTERNAL ORGANS. 



. 



PI. 35, fig. 



: punctif 

 . 65. 2. 



Proteus : mutabile. Mutable, or 



changeable. Melting Proteus, f. 66. 3. Volvox : sphoeri- 

 cum. Spherical. Vegetable Volvox, f. 67. 4. Enchelis : 

 cylindraceum. Cylindrical. Egg-shaped Enchelis, f. 61. 



5. Vibrio: elongatum. Long. Stick Vibrio, f. 68. 



Metnbranaceous. 



G.Cydiilium: ovale. Oval. Azure Cyclidium, f. 62 



7. Paramceeium : oblongum. Oblong. Paramsecium 

 chrysalis, f. 63. 8. Kolpoda: sinuatum. Crooked or 

 bent. Cuckoo Kolpoda, f. 64. 9. Gonium : angulatum. 

 With angles. Breast-plate Gonium, f. 69. 10. Bur- 

 saria : hollow like a purse. Little Swallow- like Bur- 

 saria, f. 60. 



II. THOSE THAT HAVE EXTERNAL ORGANS. 



Naked, or not inclosed in a sJtell. 



\ 1 . Cercaria : caudatum. With a tail. Green Cer- 

 caria, f. 59. 12. Leucophra : ciliatum undique. Every 

 part ciliated. Bracelet Leucophrys, f. 54 13. Trichoda : 

 crinitum. Hairy. Trichoda vulgaris, f. 55. 14. 

 Kerona : corniculatum. With horns. Kerona pul- 

 laster, f. 56. 1 5. Himantopus : cirratum. Cirrated, or 

 curled. Himantopus larva, f. 58. 16. Vorticella : cilia- 

 tum apice. The apex ciliated. Vorticella cyathini, f. 

 57. 



Covered u-ith a sliett. 



1 7. Bracfiionus : ciliatum apice. The apex ciliated. 

 Brachionus passus, f. 53. 



I. MONADS. An invisible, 1 simple, pellucid, 

 punctiform worm. 



Among the various animalcules which are 

 discovered by the microscope, these are the 

 most minute, and the most simple. The 

 monad is a small jelly-like point, eluding the 

 powers of the compound microscope, and even 

 of the single one until the recent improvements 

 in lenses had added large additional power. 

 " This genus includes the smallest forms in 

 which a voluntary motion has been observed, 

 even under the most powerful microscopes : 

 this motion, till lately, appeared to be the only 

 property of life with which they were endowed ; 

 but the observations of Dr Ehrenberg demon- 

 strate an organization equally perfect with 

 animated beings of much larger dimensions. 

 Their forms in general are simple, spherical, 

 or cylindrical masses, devoid of exlernal 

 members, or processes ; the mouth, which is 

 with difficulty discerned, is a simple orifice, 

 not furnished with ciliog, or hairs, (except in 

 one or two species) : they are colourless, and 

 transparent as the clearest crystal, yet can 

 no internal organization be seen, excepting 

 that connected with their digestive function, 

 which consists of two or more globular cavities, 

 or sacs, probably communicating with each 

 other by a tubular membrane, as in the 

 larger polygastric animalcules, but which in 



1 By invisible, is here meant indiscernible bythe naked 

 eye. 



this genus is too minute to be discerned ; 

 indeed, the stomachs or sacs themselves are 

 only to be observed when the animalcule is 

 fed with particles of colouring matter : the 

 food on which they usually exist being as 

 pellucid as themselves, the cavities are invisi- 

 ble. They increase by a spontaneous division 

 of the parent into two or more parts, and those 

 parts, or young, again divide when they have 

 attained their full age. As subjects of obser- 

 vation, the monads are principally interesting 

 from their minuteness, being as they are the 

 very limit of man's acquaintance with ani- 

 mated nature. Their diameters vary from 

 l-24000th of an inch to l-1200th, and con- 

 sequently require a very high magnifying 

 power to discern. They are numerous, and 

 generally found congregating at the surface 

 and around the decomposed matter of infus- 

 ions, either of vegetable or animal sub- 

 stances." 



To enter info particular description of the 

 various species included under the monad 

 genus, would require more space than we can 

 devote to the subject : and, indeed, of all the 

 genera, we shall content ourselves with giving 

 one, or at most two or three, special illustra- 

 tions, adding a list only of the remaining spe- 

 cies, with their distinguishing characteristics 

 appended to each. 



Plate 3 5, fig. 65. The Drop Monad." This 

 animalcule is larger than the atom monad, and 

 somewhat globular. On account of its size 

 and transparency, its digestive cavities can 

 be much more distinctly observed. It revolves 

 about its longer axis, and in swimming, that 

 part which contains the coloured particles 

 follows the colourless part. Occasionally, 

 with attentive observation, currents in the 

 water may be seen about the fore part or 

 mouth ; it is therefore highly probable that it 

 is furnished with ciliae or hairs. Those found 

 at Petersburg!! measured from 1 -3000th to 

 l-2300th of an inch in diameter : they are 

 represented in the group magnified 380 

 times." 8 



MONAD SPECIES. 



1 . Monas termo. A mere point. 2. Monns atnmus, ct 

 lens. Two species, the first appearing a simple white 

 point, and the second presenting a shining talc-like 

 appearance. 3. Monas punctum. Mere dark points, as- 

 suming under a deep power the form of short cylinders, 

 and sometimes exhibiting a slender filament 01- tail. 

 4. Monas yuttula. The Drop Monad. Described. 5. 

 Monas mica. A lucid point, assuming sometimes a 

 spherical, at others an oval form. 6. Monas tranquilla. 

 Egg-shaped. 7. Monas lamellida. Of a white colour, 

 mostly found in salt water. 8. Mo?tas pulvisculus. 

 Transparent, with a green margin. 9. Monas uva. In 

 clusters like grapes. 1 0. Monas crepuscuium. 1 1 . Monas 



2 Mr Pritchard, to whom we are indebted for much 

 of our information in this department, expresses the 

 magnifying power in linear measure, j. e. by the mag- 

 nified diameter. 



