132 Hazen: NEW SPECIES OF LOBOMONAS 
of the cells familiar in most species of Pediastrum may well 
have arisen in evolution as a consequence of the pressure and 
contact relations of the young cells in the sixteen-celled colony, 
regarding them merely as surface tension globules: nevertheless 
he has shown repeatedly that this four-lobed form does not de- 
pend in ontogeny upon the forces which may have been respon- 
sible for it originally, but that it is inherited and may reach 
full expression when there is the least possible contact with other 
cells of the colony. Repeatedly Harper calls attention to the 
view that though surface tension is commonly acting as a 
morphogenetic factor, nevertheless ‘it is the inherited anomo- 
genous consistency of the cells which is of most significance in 
determining their form.’ In strictly unicellular organisms like 
Lobomonas and Brachiomonas, there is an absence of the inter- 
action of contact and pressure stimuli which are important 
influences in the variation of the Pediastrum colony; never- 
theless in the fundamental organization of the cell the factors 
must be parallel in the main. In both cases the lobed form may 
be regarded as adaptive for the general metabolism of the cell. 
_In Pediastrum the development of spines is usually Jooked upon 
as a case of primitive differentiation for protection, and in 
Lobomonas and Brachiomonas the lobes might easily be conceived 
of as subserving a similar function: in point of fact, I have ob- 
served that when these forms are found in the same pools with 
smooth-walled ovoid Chlamydomonas cells, it is the latter that 
are devoured by protozoa, while they rarely or never prey upon 
the lobed forms, even though the latter are smaller. However, 
when two species of Chlamydomonas are present together, some- 
times one is rapidly consumed by protozoa while the other is 
ignored. The anti-selectionist, moreover, might fairly inquire 
why it is that these genera of bizarre form have produced very 
few species, in comparison with the extraordinarily successful 
genus Chlamydomonas, which has attained well nigh three score 
species, so far as taxonomy goes, in recent years. 
Wille (9, p. 19) ascribed to the zoospores of Lobomonas the 
characteristic of ‘deutliche Metabolie.’ I cannot find that 
Dangeard uses this term in connection with this genus; but as 
defined by him elsewhere* as amoeboid movement, or used 
*On désigne sous le nom de métabolie une sorte de mouvement par con- 
traction du corps particulier 4 quelques Euglénes, Amibes, Monades, etc. 
C’est ce que nous appelons mouvement amiboide. [Dangeard: aoe 
sur les algues inférieures.. Ann. Sci. Nat. Bot. VII. 7:144. 1888.] 
