A BIRD’S MODERN KINSFOLK. 205 
More landward the plover forms show a strong 
strain (9-10) onward to the crane forms vza the bus- 
tards and others; but more waterward (and it may 
be backward) is shown their remarkable kinship to 
the Gull group (9-19). The gulls should not be so 
far away as shown on the diagram, but their other 
affinities place them there. This last kinship was over- 
looked for a long time, and, as noted under eggs, is 
said to have been first observed on account of the re- 
semblance between the markings and shape of the 
egos of the two groups. To the student it is now ap- 
parent from structure. 
Returning to the cranes, they show a faint kinship 
to herons (10-15), but nothing like so close as their 
great resemblance in form would imply. In fact, we 
shall see that the heron forms get their closest ties 
from the aquatic side. It appears as if herons came 
from the water to the land, and cranes from the land 
to the water, and both becoming waders acquired 
similar structure from similar habits, a case where the 
task influenced the tool again. 
Among the crane forms is found one genus of re- 
markable birds, the seriemas, that have beaks and 
habits quite hawklike, and suggest the necessity of 
the dotted line (10-16). This group shows great va- 
riation from its most railward extremes to its most 
heronward or hawkward limit. 
Having run these landward lines let us now go up 
to the grebes, the only remaining route from the rails 
which we have not followed. Since these and all the 
divers are very low birds, and are always placed low- 
