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Aves. 
Aves. 23 
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Studies in the physiology of repro- 
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Further observations on the ana- 
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Zool. Philadelphia 34 1921 pp. 102- 
118 2 text-figs. 
550. — Pearson, T. G. Notes on the 
bird-life of south-eastern Texas. Auk 
Lancaster Pa. 38 1921 pp. 513-523 
photos. 
Pease, M. S. vide Punnett. 
Peck, M. E. vide Ritter. 
551. — Pellinkhof, J. H. Vogels van 
Meppel en omgeving. Ardea. Leiden 
10 1921 pp. 111-112. v 
Penard, T. E. vide Bangs. 
552; — Peters, J. L. A review of the 
Grackles of the genus Holoquiscalus. 
Auk Lancaster Pa. 38 1921 pp. 435- 
453. 
553. — Petronievics, P. Ueber das 
Becken, den Schultergiirtel und einige 
andere Teile der londoner Archaeo- 
pteryx pp. 1-31 2 pis. Genf. ( i.e . 
Geneva) [Georg] 1921 1. 8vo. 
554. — Peyron, A. Sur la differ- 
enciation et revolution neoplastique 
des fibres musculaires stri6es dans le 
sa 'come infectioux des oiseaux. C. R. 
Soc. Biol. Paris 84 19-21 pp. 19-22 
1 fig. 
555. — Peyron, A. Developpemcnt de 
metastases ovariennes rhabdomyoma- 
tenses dans revolution experimentale 
de la tumeur infectiense des oiseaux. 
C. R. Soc. Biol. Paris 85 1921 pp. 
655-658 3 figs. 
556. — Peyron, A. et.Lieure, C. Re- 
gression et phagocytose sur fibres 
musculaires striees dans la tumeur 
infectieuse des oiseaux. C. R. Soc. 
Biol. Paris 84 1921 pp. 656-659 3 figs. 
557. — Phillips, J. C. The status of 
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Bui. Essex Co. Orn. Cl. Salem 1921, 
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558. — Phillips, J. C. A further re- 
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559. — Pierce, W. M. Nesting of the 
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560. — Pitman, C. R. S. Oological 
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1921 pp. 15-38 73-91. 
561. — Pohl, R. Aus meinem Tage- 
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pp. 101-102. 
562. — Pohlman, A. G. The position 
and functional interpretation of the 
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delphia 35 1921 pp. 229-262 12 figs. 
563. — Pohlman, A. G. Have birds 
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Science N^w York 53 1921 pp. 439- 
440. 
564. — Poll, H. Das Zahlenver- 
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565. — Ponebsek, J. Na§e ujcde (Nos 
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172-186 8 1917 pp. 57-70 203-228 ; 
9 1918 67-84 158-176 many figs. 
566. — Poole, E. L. Impressions of 
bird-life in France. Auk Lancaster 
Pa. 38 1921 pp. 329-340 1 pi. 
567. — Portal, M. Chukor Partridges 
from Crete (breeding in captivity). 
Avicult. Mag. London 12 1921 pp. 
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668. — Portier, P. et Rorthays, R. de. 
Disparition spontanee de certains carac- 
teres sexuels secondaires chez un Coq. 
Etude histologique du testicule. C. R. 
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569. — Prater, S. H. The Arabian 
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1921 pp. 602-605. 
570. — Punnett, R. C. and Bailey, 
P. G. Genetic studies in poultry. 
III. Hen-feathered cocks. Journ. 
Genetics Cambridge 11 1921 pp. 37-57 
pis. vii-xi 2 text-figs. 
571. — Punnett, R. C. and Pease, 
M. S. Genetic studies in poultry. 
IV. On the barred plumage of certain 
breeds. Journ. Genetics Cambridge 
11 1921 pp. 235-240 2 text-figs. 
572. — Quiros, J. L. B. de. Excur- 
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Soc. Esp. Hist. Nat. Madrid 20 1920 
pp. 236-248. 
