256 University of California Publications in Zoology  \Vor.18 
Group 
Struthioniformes .... 
Crypturiformes .......... 
Apterygiformes ...... 
Spheniseiformes ...... 
Colymbiformes ........ 
Procellariiformes .... 
Ciconiiformes 
Steganopodes ........ 
ATO CAC: seccsscececcawcaces 
rlconiaene 
Phoenicopteri ........ 
Anseriformes ............ 
Falconiformes -.. 
Galliformes 5 
Opisthocomi .......... 
Mesaenatides ........ 
Gruiformes e..---------. 
Charadriiformes 
Laro-limicolae 
Alcidae 
Cuculiformes 
PSICtaCie ee sees 
Cuculi 
Coraciiformes 
Coraciaey = 
Alcedinidae ...... 
AN others 
S tri ges ees eeacessee 
Caprimulgi ............ 
Micropodii ..... ons 
Trochilidae ........ 
Colii and Trogones 
Passeriformes and 
TSANG (i eae Pere ee EE es 
DISTRIBUTION OF PLUMULES 
wo 
2 
ea 9 8 
BO ES s 
ceiee Gea! 
Ze fe = 
Be sia & 
+ 
$ pul 
xe - 
+ 
+ 
rite 
a mn 
eA + 
fer 
eee 
+or+ 
eee 
+ 
+ 
+ 
+ 
+ 
Lee 
Absent or sparse 
+ in apteria 
Pterylae only 
+, very large 
, or rudimentary 
| 
+, rudimentary in Diomedea 
+, or rudimentary 
+ 
variable 
, well-developed 
~—, rudimentary in a few genera 
, - in Pandion and Cathartidae 
large or small 
+ 
ate 
+, 
+ 
variable, usually present 
+ 
+ 
small or rudimentary 
+, large 
—, or rudimentary 
+, often rudimentary 
—, rudimentary in Aluco 
small or — 
+, not highly developed 
evolution, if this hypothesis be true, resulted in the segregation of 
contour feathers into tracts, and the reduction of plumules, first 
between the contour feathers, and finally on the whole body, culmi- 
