Feather development non-nervous. They have a tubular central shaft called the rachis; coming off either side of the rachis are the veins, which have a series of barbs with interlocking connections that are called barbules. The rachis and attached veins make up the spathe. The opposite of the rachis is the calamus, which anchors the feather to the body and is moved by attached dermal muscles. There are many different types of feathers that mostly follow this basic design with few variations based on evolutionary needs. Feathers are sometimes referred to as “elaborate reptile scales” just as birds are sometimes viewed as
Calamus (DTP) for its support for automatic kerning even where adjacent characters are set in different fonts or at different sizes. Its high modularity offers features for almost every purpose in desktop publishing. Calamus also was one of the first DTP apps to support real virtual objects and frames, nondestructive vector masks, and editable PS/PDF import. Its (adjustable) measurement base of 1/10,000mm allows accurate positioning of elements. Calamus was ported to Windows by MGI Software and was released as Calamus 95. The current version of Calamus is Calamus SL 2015, also available as SLC 2015 (complete edition with all additional modules) and