664 
Mr. It. Shelford on the Pterylosis of the 
feathers, at first, are in two rows, but shortly thin out 
to one row only. From this description it will be seen 
that this tract has now approximated quite closely to 
the adult condition, a further extension of the outer 
branch being all that is needed to make them identical. 
As a result of the great development of the feathers 
on the throat and neck, it is now no longer possible 
to distinguish a pteryla colli lateralis: the apterium 
between that former tract and the pt. spinalis is still 
apparent, and in fact persists even in the adult, but 
each half of the tract has now, so to speak, joined hands 
across the formerly unclothed gap of the throat and 
become confluent with and indistinguishable from the 
pt. ventralis. The meagre trichoptiles which in Stages 
1 and 2 marked the pt. colli lateralis and (incompletely) 
the pt. ventralis have now totally disappeared. 
Pt. caudce (fig. 4, p. 661, pt. caud.f —The sheaths of the ten 
rectrices and their coverts are now prominent: all bear 
trichoptiles. 
Pt. alaris .—All the feather-sheaths have now pushed through 
the skin, and in a few cases some of the feathers have 
just begun to break through their sheaths ; the few 
trichoptiles that persist are much worn. The arrange¬ 
ment of the tract differs so slightly from that described 
under Stage 2, that I have but few remarks to add. 
Outer aspect .—On the manus there are now five tectrices 
mediae and five tectrices minores, and one row of 
tectrices margin ales along the pre-axial edge. 
The carpal remex is still much smaller than its 
covert. 
No new feathers have appeared on the cubitus; the 
gap between the tectrices majores and tectrices mediae 
is as apparent as ever; the parapteron is now con¬ 
tinuous with the former series. There is a bare tri¬ 
angular space on the patagial membrane. 
The ala spuria has four feathers with their coverts, 
continuous, as before, with the covert series of the 
cubitus. 
