MONADS. 



[ 508 ] MONOCOTYLEDONS. 



Dujardin's characters are : animalcules 

 without an integument, consisting of a glu- 

 tinous, apparently homogeneous substance, 

 susceptible of becoming agglutinated to 

 other bodies, and so drawn out and altered 

 in form, with one or more flageUiform fila- 

 ments as locomotive organs, and sometimes 

 lateral or tail-like appendages. 



BIBL. Ehr. Infus. 1; Duj. In/us. 270; 

 Dallinger, M. M~Jn. xiii. 185 ; Cienkowski, 

 chultze's Arch. xii. 227. 



MONADS are species of Monas, or other 

 Monadina. 



MONAS, Mull. A genus of Infusoria, of 

 the family Monadina. 



M. Dauingerii. Ovate, pointed, no nucleus 

 nor contractile vesicle ; length 1-4000". In 

 fish- (cod) macerations. Propagation by 

 transverse fission ; and by spores after con- 

 jugation and encystment. The germs of 

 these monads survive a temperature which 

 destroys the adults. 



M. vinosa, E. Ovate, uniformly rounded 

 at each end, of a red-wine colour, motion 

 slow and tremulous. Length 1-12,000 to 

 1-6000". 



Found upon the sides of glass vessels in 

 which decaying vegetable matter has been 

 kept, on the side next the light. 



M. lens, D. (PI. 31. tig. 44 a). Body 

 rounded or discoidal and tubercular. Breadth 

 1-5200 to 1-1800". 



One of the most common organisms in 

 animal and vegetable infusions. We have 

 found one common in animal infusions 

 (PI. 31. fig. 44 6), perhaps the same as the 

 above ; but it possesses usually two fila- 

 ments : on the left side is one without fila- 

 ments, but with the body drawn out from 

 adhesion to the slide. 



M. attenuata, D. (PI. 31. fig. 44 c). Body 

 ovoid, narrowed at the ends, nodular, un- 

 equal ; filament arising from the anterior 

 narrowed portion. Length 1-1600". Very 

 abundant in fetid films floating on water 

 containing decaying freshwater Algae. 



M. prodigiosa, see MICROCOCCUS. 



Several other species ; many probably 

 consisting of the zoospores of Algse, or the 

 swarm-germs of other Infusoria. 



BIBL. Ehr. Infus. 3-, Duj. Infus. 279; 

 Kent, Inf. 232. 



MONE'RA, Haeckel. A group of Pro- 

 tista, forming the simplest of all organisms, 

 the protoplasm or sarcode constituting the 

 whole structureless body; nuclei and cell- 

 membranes are never developed. The Mo- 

 nera are subdivided into Gymnomonera and 



Lepomonera. The Gymnomonera do not 

 pass into a quiescent or resting condition, 

 and do not surround themselves with a 

 covering, and propagate by fissiparous divi- 

 sion. The Lepomonera pass into a resting 

 stage, and surround themselves with a co- 

 vering for the purposes of reproduction 

 breaking up into spore-like bodies, which, 

 on escaping, resemble the parent form. 



BIBL. Cienkowski, Schnitzel Arch. 1865, 

 i. 203 ; Haeckel, Zeit. wiss. Zool 1865, xv. 

 360 ; Gener. Morph. Jenai. Zeit. 1868, iv. ; 

 Wright, Qu. Mic. Jn. 1869. 



MONOCER'CA, Bory. A genus of Ro- 

 tatoria, of the family Hydatinaea. 



Char. Eye red, single, cervical; foot-like 

 tail simply styliform. 



Gosse mentions a second eye situated in 

 the breast of one species. Ehrenberg de- 

 scribes three species, to which Gosse adds 

 two. 



M. rattus, E. (PI. 44. fig. 9). Body ovate- 

 oblong; forehead truncate, unarmed; foot 

 styliform, as long as the body. Aquatic. 

 Length 1-120". 



BIBL. Ehr. Infus. 422; Gosse, Ann. N. H. 

 1851, 199. 



MONOCOTYLEDONS. One of the 

 classes of Angiospermous Flowering Plants, 



Fig. 461. 



Reduced view of a stem of a Palm, showing the per- 

 pendicular and horizontal section, in which the fibro- 

 vascular bundles F.V are seen isolated in the medullary 

 parenchyma. 



so called from the structure of the embryo 

 contained in the seed, which in a large num- 

 ber of cases is of microscopic dimensions, 

 and always requires the use of the simple 

 microscope for its dissection. Some of the 

 families placed under this head have usually 

 an acotyledonous embryo, as Orchidaceae ; 



