Sinornithosaurus form from those found on birds from the same geological deposits. The body (contour) feathers were generally between 3-4.5 cm long and included two types: the first type are formed of several filaments joined together into "tufts", similar to modern down feathers. The second type, including those on the arms, were composed of rows of filaments ("barbs") joined together along a main shaft ("rachis"), making them similar in structure to modern bird feathers. However, unlike the wing feathers of flying birds, they did not have the secondary branches with tiny little hooks ("barbules") that flight feathers have, which allow the
Calamus (poems) This cluster of poems contains a number of images and motifs that are repeated throughout. The most important is probably the Calamus root itself. "Acorus calamus" or Sweet Flag is a marsh-growing plant similar to a cat-tail. Whitman continues through this one of the central images of "Leaves of Grass"--Calamus is treated as a larger example of the grass that he writes of elsewhere. Some scholars have pointed out, as reasons for Whitman's choice, the phallic shape of what Whitman calls the "pink-tinged roots" of Calamus, its mythological association with failed male same-sex love and with writing (see Kalamos), and