. The animans and man; an elementary textbook of zoology and human physiology. ones, with thin bare stem and smallterminal tuft of branches,are called thread feathersor filoplumes. Pull a quill feather fromthe wing and examine it indetail. Note the central stemor shaft, composed of twoparts, a basal hollow trans-parent quill, which bears noweb and by which the feath-er is inserted in the skin, andc ,. a longer terminal four-sided FIG. 6. Bit of birds feather, great-ly magnified; s, shaft; 6, barb; part, the rachis, which bearsbl, barbule; h, hamule. On either side a web or vane. Examine the va
. The animans and man; an elementary textbook of zoology and human physiology. ones, with thin bare stem and smallterminal tuft of branches,are called thread feathersor filoplumes. Pull a quill feather fromthe wing and examine it indetail. Note the central stemor shaft, composed of twoparts, a basal hollow trans-parent quill, which bears noweb and by which the feath-er is inserted in the skin, andc ,. a longer terminal four-sided FIG. 6. Bit of birds feather, great-ly magnified; s, shaft; 6, barb; part, the rachis, which bearsbl, barbule; h, hamule. On either side a web or vane. Examine the vane with a lens and see that it is composed of many nairow linear platescalled barbs, and that each barb is fringed in turn with smallerbranches called barbules. Finally, each barbule bears manyfine barbicels or hamules, which can be seen with a micro-scope. The barbs comprising the vanes are interlockedwith each other (fig. 6), thus forming a true web and givingthe vanes, composed of small, weak parts, much strengthand power of resistance. Rub the feathers from tip to base,. bl-. THE SUNFISH AND THE SPARROW 15 and, examining the vanes with the lens, find out what hashappened; now rub from base to tip, and note, under alens, the result. Examine a plucked-out contour feather. HOWT does itdiffer from the quill feather? Can you understand itsstructure from your study of the quill feather? Note thatthe tip of the feather is colored and marked while the baseis not especially patterned. Why is this ? Examine a downfeather. How does it differ in make-up from a quill feather?From a contour feather? What is the special use of thedown feathers? Finally, pluck out one of the hair-likethread feathers from the base of the bill and examine it withthe lens to determine its structure. Make a careful drawing of each of the four kinds offeathers, naming all the parts. In classifying birds reference is made in the manuals ofclassification to differences in the shape and characterof many parts of t
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Keywords: ., bookcentury1900, bookd, booksubjectphysiology, booksubjectzoology
