304 Universitij of California Publications in Zoology I Vol. 13 



the more distal ones shorter and not .so delicate, often more or less 

 appressed to the shaft; towards tip dorsal eilia 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 hase of barbs, 

 with distal barbules almost identically like those of inner vane of 

 remiges, but with pennula longer, and dorsal barbieels weaker. 

 Proximals, like 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 hreast 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 distinct. Terminal 

 portion of barb, however, entirely transformed. Distal barbules 

 (pi. 17, fig. lOe) with a series of flexules continuous with dorsal 

 pennular series of barbieels except in booklet region; base narrow, 

 and no marked bend between base and pennulum. As shown in 

 figure, all barbieels, even booklets, have tendency to bifurcate. 

 Proximal barbules also develop flexules, becoming similar in form 

 to that in Oceanodroma melania (pi. 17, fig. 126). 



h) 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 

 llo-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 distinct, 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. 



Oceandroma 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- 



