APPENDIX. 471 



cetan were presently observed isolated hyaline protoplasmic spheres having the 

 same diameter and structure as the contents of the spore-cases, just described. In 

 a little while the exit of one of these hyaline spheres from the echinulate spore-cases 

 was witnessed, and the relationship between the two substantially established. 



By the termination of the third day, these protoplasmic spheres had much 

 increased in number, some of them exhibiting feeble amccboid movements. An 

 addidonal factor had, however, now appeared upon the scene in the form of a 

 vermicular monadiform organism, having a length of 1-1250" to i-iooo", and 

 which progressed somewhat clumsily through the water revolving on its longitudinal 

 axis. A spheroidal nucleus, with its enclosed nucleolus, was observable towards 

 the anterior extremity, and a single rhythmically contracting vesicle at the opposite 

 region of the body. The derivation of these monadiform beings, from the extruded 

 protoplasmic spheres, was immediately suspected, and the correctness of this 

 inference soon substantiated. Selecting an isolated and recently extruded sphere, 

 it was carefully watched. For a considerable interval the newly released germ 

 confined its signs of vitality to a feeble expansion and contraction of its peripheral 

 margin, and to the rhythmical pulsations of its contractile vesicle, which, with the 

 spheroidal endoplast, were clearly discernible. As time progressed, alterations in 

 contour were more strongly manifested, though without the germ moving away from 

 the scene of its birth. At length an altogether elongate amoeboid, or vermiform 

 aspect predominated, the nucleus or endoplast being shifted to one extremity and 

 the contractile vesicle occupying the other. Then, all at once, a flickering at one 

 end indicated the development of a flagellate appendage, which in a few seconds 

 became distincdy visible. The vibratile motion of this organ soon caused the body 

 to oscillate, and presently lifting it from its hitherto prone position, it was launched 

 into the surrounding water a free-swimming, elongate monad. During the next 

 few days, similar monadiform germs were developed abundantly from the spores in 

 all parts of the field, and the next step in their ontogeny fully certified. It was found, 

 in fact, that the free-swimming condition of the germs was but of brief duration, and 

 subservient, apparently, only to their local distribution. Within a day or two, 

 the monadiform beings once more betook themselves to a repent mode of existence, 

 the flagella being for a while retained, communicating to them a remarkable hkeness 

 to the repent flagelUferous animalcules heretofore described under the generic titles 

 oi Mastigamoiba and Rcptomonas. The flagella being next completely withdrawn, the 

 organisms became undistinguishable from ordinary A/ncebcB, and continued to creep 

 about the field by broad, ovate extensions of their periphery. 



An important point yet remained to be solved. De Bary and Cienkowski had 

 declared that during both their monadiform and subsequent amoeboid phases the 

 Myxomycetes ingested and subsisted on solid food. This evidence has been 

 regarded by some writers as extremely doubtful, while by others it has been 

 emphatically denied. A simple experiment, however, soon demonstrated that these 

 two authorities were again completely in the right. Examples, more especially of 

 the repent amoeboid units, had been previously observed, whose bodies contained 

 vacuoles more or less completely filled with ingested Bacteria, which, being produced 

 in numbers prior to the hatching out of the Physanim germs, provided for the 

 Mycetozoa an abundant and ready set feast. The common test of adding pulverized 

 carmine to the water, was speedily followed by its free ingestion by both the 

 natatory monads and the repent amoebiform units, the former incepting it chiefly 

 towards the anterior region of the body, and the latter indifferently at any point of 

 their periphery. As in the case of Bacteria, the smaller particles of pigmentary 

 matter, after inception, were usually collected together within spheroidal vacuoles 

 of the endoplasm, and maintained' there the same molecular movements they 

 exhibited in their free condition. The larger parUcles, on the other hand, remained 

 distributed as more or less disdnctly isolated fragments. For the next few weeks, 

 these amoeboid organisms continued to feed and increase in size, and were fairly 

 started on their way towards the succeeding chapter in their ontogeny, viz. their 

 production, through coalescence, of the comparatively colossal but still amoebiform 

 " Plasmodia," out of which the spore-receptacles or sporangia are finally evolved. 



