358 University of California Publications in Zoology  \Vou.13 
In the Laridae and Alcidae the down barbules are shorter, with 
indistinct nodes on the proximal portion, and well-developed prongs 
distally, thus very closely resembling the Colymbiformes. 
ad) Relationships 
The unquestionable likeness of the structure of feathers in the 
Alcidae to that in the Colymbiformes very strongly suggests the 
close relationship between them. The relation of the Laridae to 
the Alcidae, and of the Limicolae to the Laridae, is just as plainly 
indicated, and we have a very clear and distinct path of evolution 
suggested by these groups. Relationship to the Gruidae is also 
suggested and it is probable that the latter represent an early off- 
shoot from the limicoline stem. The Limicolae, in all respects, show 
higher specialization than the other forms included in the suborder. 
e) Summary 
The Laro-limicolae are characterized as follows: 
(1) Plumules evenly distributed, though sometimes sparse in the 
Limicolae. 
(2) Aftershaft present, sometimes small. 
(3) Distal barbules of remiges with broad subnuclear area on 
base, very small ventral teeth, rather short, subequal hooklets, a series 
of subequal, somewhat curved ventral cilia, and on inner vane two 
proximal dorsal cilia more or less earlike. 
(4) Proximal barbules with very slender base, inconspicuous 
ventral teeth, and pennulum little if any over half length of base; 
proximals of outer vane with imperfectly developed ventral cilia. 
(5) Distal barbules of back feathers with a long series of well 
developed, curved, ventral cilia. 
(6) Breast feathers with barbules on outer portion of barbs with 
flexules. 
(7) Down resembling that of Colymbiformes in Laridae and 
Alcidae, the barbules with enlarged nodes and more or less pig- 
mented in Limicolae. 
Suborder PreRoOcLO-COLUMBAE 
Plate 29 
This suborder includes two rather distinct and well-defined 
groups, the Columbae with the pigeons and doves on the one hand, 
