INTRODUCTION. 19 



ciliary line, a stripe immediately above the eye. Vermicnla- 

 <iore, very fine " waves." ^ aigni&es the male, 5 the female; 

 ^signifies "equal to," >■ "more than," and •< "less than." 

 " Inch " or " inches " is abbreviated to in., and decimal num- 

 bers (written with a dot before) generally indicate hundredths 

 of an inch. 



Except where there are indications to the contrary, the 

 " upper parts " generally include the upper surface of the 

 wings and tail ; but the " under parts " frequently refer to 

 the body only. The " crown " includes the forehead (or even 

 the nape too). The "rump" (or lower back) often includes 

 the upper tail-coverts, the " belly," the under tail-coverts, etc. 

 The " sides " invariably refer to those of the breast and belly. 



§ U. Measurements of both birds and eggs are made in 

 straight lines between two points. To measure the length of a 

 bird, lay it on its back, and make the tip of the bill (so far as 

 reasonable), and the end of the longest tail-feather, touch the 

 ruler or paper on which they are laid ; then measure the dis- 

 tance between these points. Measure (with compasses) the 

 tarsus in front, and the bill from the tip of the upper man- 

 dible to the feathers actually or apparently belonging to the 

 forehead.^* The " depth " of a bill is its vertical width near 

 the base, when closed. Eggs may be measured by dividers, 

 or by a ruler with a slide. Eor accurate measurements a 

 ruler marked decimally (or even with hundredths) is best. 

 ^ of an inch equals about .06. 



§ V. Birds as a class are composed of subclasses ; these 

 are grouped into orders (such as the Raptores or " birds of 

 prey "), which are divided into families (as the Raptores 

 into StrigidcB, Fcdconidce, etc., or the Hawks, includiug 

 Eagles, the Owls, and the Vultures). The orders are some- 

 times more primarily divided into suborders, and families 

 into subfamilies. Thus the Passeres consist of the Oscines 

 or singing passerines, and the Clamatores or non-singers ; ^^ 



^* There are other methods of mak- ^ A rather technical distinction, 

 ing this measurement: 



