304 University of California Publications in Zoology (Vou. 138 
the more distal ones shorter and not so delicate, often more or less 
appressed to the shaft; towards tip dorsal cilia also developed. 
Pennulum 1 mm. or more in length, 0.01 mm. wide. 
(2) Other Feathers 
Secondaries differ from primaries in having pennula, especially 
of distals, greatly increased in length, like the pennula of prox- 
imals of outer vane of primaries. Back feathers, near base of barbs, 
with distal barbules almost identically like those of inner vane of 
remiges, but with pennula longer, and dorsal barbicels weaker. 
Proximals, lke those of outer vane of remiges, having very long, 
heavy, barbicelled pennula towards tip of barb, but only 4 or 5 
slender, wavy teeth on more basal part of barb. On distal portion 
of barb, i. e., approximately distal third, flexules developed on 
distal barbules, but transformation of barbules slight as compared 
with breast feathers. 
In breast feathers proximal portion of barbs not materially dif- 
fering in structure from that of back feathers, except that barbules 
are weakened and the characteristic features less distinet. Terminal 
portion of barb, however, entirely transformed. Distal barbules 
(pl. 17, fig. 10e) with a series of flexules continuous with dorsal 
pennular series of barbicels except in hooklet region; base narrow, 
and no marked bend between base and pennulum. As shown in 
figure, all barbicels, even hooklets, have tendency to bifureate. 
Proximal barbules also develop flexules, becoming similar in form 
to that in Oceanodroma melania (pl. 17, fig. 126). 
b) Other Types 
In Puffinus griseus the structure of the remiges is very similar 
to that of Diomedea. All barbules, as shown in plate 17, figures 
lla-c, though smaller, and with the characteristic features less 
conspicuous, nevertheless differ in no essential points. The back 
feathers of this species have the characteristic details of structure 
still less distinet, the dorsal prongs and dorsal cilia of the distal 
barbules, and the wavy form of the ventral teeth of the proximals, 
being undeveloped. The breast feathers have the same structure 
as in Diomedea. 
Occandroma melania has the minute structure of the remiges 
very much like that of Puffinus, though the barbules, of course, 
are smaller, the base being about 0.3 mm. long, (relatively very 
large, except in this order) and with the same conspicuousness of 
the twist at the junction of the base and pennulum, but the dorsal 
prongs of the base are exceedingly minute or missing entirely. In 
all other details, the structure is essentially the same as in Dio- 
medea and Puffinus. 
The back feathers of Oceanodroma melania have a weak struc- 
