or THE PHTTOZOA. 193 



and the subsequent fission may be arrested at any point, so that either a few 

 sections which, in the phi'aseology of botanists, may be called macrogonidia, 

 or other^vise very numerous small ones, or microgonidia, may be developed. 



As the simply encysted Euglence have been represented as independent 

 genera of plants, so the same thing has occurred when their contents have 

 been seen in the process of self- division ; thus, for instance, Perty thinks it 

 probable that Protococcits turgidus and P. clialyheus (Kiitz) are no other than 

 two such transitional conditions. 



Another circumstance attending encysted Euglena', is the forming an attach-^ 

 ment to other bodies by a sort of pedicle, which extrudes from what has been 

 the anterior extremity of the being. "When viewing large collections of Eu- 

 glence, specimens may occur of two or several united together by the head or 

 tail, sometimes with the tail of one to the head of another. Examples of two 

 partially united have been explained by supposing the act of fission of a 

 parent-animal to be nearly accomplished ; but other observers have seen in 

 such united beings an instance of conjugation, i. e. of an act, to some degree, 

 of impregnation. The union, however, of several by the tail, sometimes seen, 

 is an argument against this supposition, and is rather suggestive that such 

 combinations are the remnants of primitive adhesions betwei3n gonidia within 

 the parent-cell or between germs before a pellicle has formed around them, 

 or, agaiuj that a mucoid matter thrown out from the surface, as happens in 

 many Phytozoa, may constitute the band of union, when incomplete fission or 

 persistent primitive adhesions cannot be considered its origin. There is cer- 

 tainly no a priori argument against the occurrence of conjugation in this family, 

 and some naturalists would, from analogy with related beings, look for it ; 

 but at present it has not, we think, been proved. 



Ovules or germs. — That Euglence reproduce by internal germs is an opinion 

 now advocated by several naturalists. To oiu^ minds this mode of propagation 

 is really homologous with the formation of gonidia in admitted plants. Kol- 

 liker vmiea (J. M. S. i. p. 34) — " Multiplication by means of germs generated 

 in the interior indubitably occurs in certain Infusoria : in Euglena four to six 

 embryos are seen in one individual, entirely filling it, which at length, fur- 

 nished with their red speck and filament, break through their parent, leaving 

 it as an empty case." 



Mr. Carter {op. cit.) has entered very largely into an account of the ovules of 

 Infusoria and of their development. " In Euglena viridis/^ he writes, " the 

 ovules are of an oblong shape : they are found, like those oi Spongilla, scattered 

 over the sides of the vessel, and evidently have in Kke manner the power of 

 locomotion in addition to that of turning upon their long axis when otherwise 

 stationary .... The pellucid central area in them corresponds with the oblong 

 shape of the capsule ; but beyond this and the central granule I have not 

 been able to follow their development out of the parent, though, from the 

 number of young E. virklis present, it may be reasonably inferred that they 

 came from the ovules. The young Euglence, however, being so rapid in their 

 movements when once the cilium is formed, it can hardly be expected that, 

 except imdcr a state of incarceration, their development can be followed so 

 satisfactorily as that of the slow-moving Rhizopocl. Instances do occui', how- 

 ever, where the ovules gain the cilium within the cell, and there bound about 

 when fully developed like the zoospores of Algae ^^-itliin theii' spore- capsules. 

 In this way I have seen them moving rapidly within the effete transparent 

 capsuled body of E. viridis and in Crumenula texta, where the spiral-fibre 

 layer is so strongly developed as to retain the form of the Euglena for a long 

 time after all the soft parts have perished. On these occasions the embryos 

 are perfectly colourless, with the exception of a central point which reflects a 



