GLOSSARY. 625 



Middle Toe. The third toe in order of reckoning, with few exceptions fonr-jointed. 

 When the fourth toe is reversed, it becomes the outer anterior toe ; in a few birds in 

 which the true inner or second toe is wanting, it becomes the inner anterior toe. It 

 is never versatile. It rarely has only three joints like the second toe. 



Middle Wing-coverts or Median Coverts. The series of upper coverts of the secondary set, 

 situate in one or more rows between the greater and lesser ceverts. They are usually 

 recognized by their overlapping each other in the reverse direction (i. e. inner border 

 of one overlapping outer border of the next one) from the others, whence they are some- 

 times called tectrices perversa. 



Migration. Periodical (but sometimes irregular) jonrneyings, or changes of abode, of 

 birds at certain seasons, to secure food, climate, or other physical conditions of environ- 

 ment best suited to' their wants. Migration is generally meridional (north-south) and 

 believed by some to be mainly accomplished along a magnetic meridian ; but it is 

 often quite otherwise, influenced by topography, etc, or altogether capricious. In the 

 Northern Hemisphere, verual migration is northward, the autumnal in the opposite 

 direction. 



Monogamous. Fairing ; mating with a single one of the opposite sex. Birds of which 

 the male assists in incubation and care of the young are called douhly monogamous. 



Mucronaie. Spine- tipped, as the tail of a swift. 



N 



Naris, pi. Narea. The nostril. 



Nasal. Pertaining to the nostril. 



Natatorial. Capable of swimming ; belonging to swimming birds. 



Nidifieation. Nest building ; mode of nesting. 



Nomenclature. The snm of the words or terms peculiar to any department of knowledge ; 

 as, ornithological nomenclature ; in this sense equivalent to terminology. Also, the nam- 

 ing of objects according to some fixed principle ; as, the binomial nomenclature. It is 

 essential to the integrity of nomenclature that it should rest upon classification or 

 taxonomy. 



Nucha. Nape ; upper part of ceryix, next to occiput. 



Nuchal. Pertaining to the nape. 



o 



Ohsoure. Dark ; not evident ; little known ; faintly marked. 



Occipital. Pertaining to the hind head. 



Occiput. The hind head. 



Ochrey, Ochreous. Celor of yellow ochre. 



(Esophagus. Gullet ; tube conveying food from mouth to stomach. 



Olivaceous. Of a mixed green and brown color. 



Oology. Science of birds' eggs. 



Order. In classification a group between family and class. 



Ordinal. Having the taxonomic rank or value of an order. 



Osdnes. A. group of singing- birds, possessing a complex vocal organ of numerous 



syringeal muscles, conferring musical ability. These are regarded as the highest or 



most perfectly developed of their class. 



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