GENUS ANTHOPHYSA. 269 



and is fused with the conjoined posterior extremities of the monad groups. In this 

 region, moreover, the consistence of the pedicle is so soft and flexible that it allows 

 the attached group of monads to gyrate or spin freely backwards and forwards 

 upon its stalk in response to the active vibrations of the innumerable flagella. Not 

 unfrequently, owing to diminution in quantity and quality of the building material 

 used in the fabrication of the stem, it becomes incapable of further supporting these 

 actively motile groups, and snapping through, sets them free in the form of those 

 simply spheroidal clusters so closely resembling superficially the permanently free 

 spheroidal colonies of Uvclla or Synura, with which they were originally confounded. 

 Examples of such free-floating clusters or "ccenobia," as delineated respectively by 

 O. F. Miiller and Friedrich Stein, are given at PI. XVII, Fig. 15, and PI. XVIII. 

 Figs. 2, 4, and 5. The substance of the adult stem of Anthophysa vegetans is 

 apparently at first_ sight horn-like and homogeneous, and similar to that out 

 of which the loricae and pedicles of many higher Infusoria are composed. 

 Usually a nature akin to chitine is ascribed to this substance, but its affinity is 

 probably much nearer to that of keratose or keratine, the basal substance of the 

 skeletal framework of the fibrous or horny sponges. The comparatively firm con- 

 sistence of the adult pedicles of the present species readily accounts for their long 

 duration, they being frequently met with even after the monads have died away ox 

 become dispersed. Examined more minutely, it is found that the pedicle of 

 Afit/iop/iysa vegetans, in place of being homogeneous, is, as shown in PL XVII. 

 Figs. 16 to 18, striated longitudinally, the number of strice increasing with the pro- 

 longation and corresponding greater diameter of the stem, but not themselves under- 

 going any alteration in their respective diameters. 



By feeding a colony of these animalcules with pulverized carmine the significance 

 of the stem with its mode of growth and striated structure became at once apparent. 

 The administered pigment was so greedily ingested, that within a few minutes the 

 body of each monad was gorged with brilliant particles, which regurgitated freely 

 within the body-sarcode after the manner of the food-pellets in Codosiga or Vorticella. 

 It was not long, however, before the discovery was made that there was little or 

 no nutritive matter in this pigmentary substance, and its rejection thereupon com- 

 menced. This was eff"ected entirely at the posterior extremity, or point of union 

 with the pedicle, of each independent animalcule. In this species each member of 

 the large spheroidal cluster radiates from the same terminal point of a single 

 branchlet, and thus the separate contributions of rejected particles proceeding from 

 each individual, become concentrated at their point of exit into one united stream. 

 A change, however, now came over the aspect of the pedicle itself, for the particles 

 of discarded material, instead of falling away as waste, and accumuladng round the 

 base of the pedicle as was observed of Oikomonas obliquus, were actually utilized as 

 material out of which to build up and prolong it. The amber colour and striated 

 appearance which had previously characterized this structure disappeared, and the 

 pedicle now continued increasing rapidly in length, composed entirely of particles 

 of carmine bound together by a small admixture of glutinous material passed 

 from the monads' bodies. So rapidly and abundantly indeed were the carmine- 

 particles received and discharged, that within half an hour the pedicle of one 

 group had nearly doubled its former length, and continued growing at the 

 same rate until a very abnormal and striking efl"ect was produced. The general 

 aspect of an example of Anthophysa vegetans with such an artificially constructed 

 stem is illustrated at PI. XVII. Fig. 18, and in which instance the whole of the 

 pedicle from the point a represents the portion that was produced in the space 

 of half an hour. In other instances the process of assimilating the carmine was 

 carried on for a still longer interval, the result in such cases being that, missing its 

 customary strength, the pedicle bent upon itself, forming a loose, flexible loop as 

 shown at Fig. 19. Under ordinary condidons the growth of the pedicle is a much 

 slower process, the pabulum out of which it is built not being usually so abundant, 

 and consisting of more easily digested animal and vegetable particles, which 

 weld together into a more compact and homogeneous mass. The stem-producing 

 property of Anthophysa under such ordinary conditions may in fact be compared 



