PERISTEILE: TRUE COLUMBINE BIRDS. 707 



{Geopliaps). When there are a pair of notches on each side, the outer processes are short, as 

 in Gallince. Furculutn well developed and complete (it is reduced in the flightless Didi) ; 

 pectoral crest of humerus, salient, acute. Carotids two. Syringeal muscles one pair. Coeca 

 coli small, rudimentary, or wanting; gizzard muscular; crop developed; gall-bladder generally 

 absent (present in Carpophaga, etc.). Fourth glutaeal muscle undeveloped; second pectoral 

 specially inserted ; ambiens normally present, or wanting ; deep plantar tendons desmopel- 

 mous, that of the hallux alone supplying its own digit. Oil-gland nude, small, or wanting. 

 Plumage without aftershafts, or with only very small ones; wings aquintocubital ; spinal 

 pteryla well defined, forked over the shoulders. Feet insessorial ; hallux normally insistent, 

 in some terrestrial genera somewhat elevated and shortened ; tarsus normally scutellate in 

 front, reticulate on the sides and behind, rarely entirely reticulate (Gouridfe). Rectrices nor- 

 mally 12 or 14, exceptionally IG or 20. Primaries 11. Altricial; psilopaedic ; monogamous; 

 nidificant ; eggs ordinarily one pair, white. 



The PeristercB will be immediately recognized by their likeness to the familiar inmates of 

 the dove-cot. One seemingly trivial circumstance is so constant as to become a good clue to 

 these birds : the frontal feathers do not form antife by extension on either side of culmen, but 

 sweep across base of bill with a strongly convex outline projected on culmen, thence rapidly 

 retreating to the commissural point. The plumuleless plumage is generally com])act, with 

 thickened, spongy rhachis, the insertion of which will seem loose to one who skins a bird of 

 this suborder. The head is remarkably small ; nock moderate ; body full, especially in the 

 pectoral region. The wings are strong, generally lengthened and pointed, conferring a rapid, 

 powerful, whistling flight ; the peculiar aerial evolutions that these birds are wont to perform 

 have furnished the synonym Gyrantes. The tail varies in shape, from square to graduate, but 

 is never forked ; as a rule tliere are 12 rectrices, frequently increased to 14, as in nearly all the 

 Treronidfe, rarely to 16 in the genera Thoracotreron, Phaps, and whole family Gouridcc, ex- 

 ceptionally to 20 in the genus Otidiphaps ; all the North American genera have 12, excepting 

 Zenaidura, with 14. The feet show considerable modification, when strictly arboricole are 

 compared with more terrestrial species ; their general character has been indicated above. The 

 gizzard is large and muscular, particularly in species that feed on seeds and other hard fruits ; 

 tlie gullet dilates to form a capacious circumscribed crcqi, divided into lateral halves, or tend- 

 ing to that state. This organ at times secretes a peculiar milky fluid, which, mixed with 

 macerated food, is poured by regurgitation directly into the mouth of the young; thus the 

 fabled " pigeon's milk" has a strong spice of fact, and in this remarkable circumstance we see 

 probably the nearest approach, among birds, to the characteristic function of mammals. " The 

 voice of the turtle is heard in the land " as a plaintive cooing, so characteristic as to have 

 afforded another name for the suborder, Gemitores. Pigeons are altricial, i)silopa;dic, and mo- 

 nogamous — doubly monogamous, as is said when both sexes incubate and care for the young ; 

 this is a strong trait, compared with the pryecocial, ptilopajdic, and often polygamous nature 

 of rasorial birds. They are amorous birds, whose passion generally results in a tender and 

 constant devotion, edifying to contemphito, but is often marked by high irascibility and jnig- 

 nacity — traits at variance with the amiable meekness which Doves are supposed to symbolize. 

 Tlicir bliinduess is supposed to be due to absence of tiie gall-bladder. The nest, as a rule, is 

 a rude, frail, flat structure of twigs; the eggs are usually 2 in number, sometimes 1, wliite ; 

 when 2, supposed to contain the germs of opposite sexes ; the period of incubation is usually 

 between 2 and 3 weeks. 



" The entire number of Pigeons known to exi.^^t is about 300 ; of these tin- Malay Archi- 

 pelago already counts 118, while oidy 28 are found iu India, 23 in Australia, less tlian 40 in 

 Africa, and not more than 80 iu the whole of America." (The total number of species now 

 known is about 475, but this increase over fortnerly known ones does not materially atfect tlie 

 relative proportions of the figures here said.) Tliey focus in the small district of whicli New 



