POULTRY NOTES — 1909. 1 19 



POULTRY ABNORMALITIES. 



During the past year two papers* dealing with abnormalities 

 of poultry have been published. One of these deals with a case 

 of hermaphroditism and the other with an abnormal egg. The 

 purpose of studying such abnormalities as these is to gain light 

 from them in an indirect way on the normal physiology of egg 

 production. An abnormal specimen is, in a sense, the result 

 of an experiment performed by nature. From such specimens 

 facts of great importance for the interpretation of normal pro- 

 cesses may often be learned. 



The hermaphrodite specimen may be first considered. From 

 a chick hatched in the spring of 1907, at the Maine Agricultural 

 Experiment Station, there developed the bird which forms the 

 subject of this abstract. This bird was a Barred Plymouth 

 Rock and when adult presented externally the general appear- 

 ance of a normal hen of this variety, so far as the characters 

 body form and plumage color were concerned (cf. Fig. 81). 

 As the photograph in Fig. 81 shows, however, the head and 

 neck resembled these parts in a cockerel. This resemblance was 

 especially remarkable in respect to the size and shape of the 

 comb and wattles. The comb was obviously much larger than 

 the comb of a normal Barred Plymouth Rock hen and looked 

 exactly like the comb of a male bird. This was also true of 

 the wattles. 



The dimensions* of the comb of this bird were as follows: 



Length 88.4 mm. 



Calculated height 25.1 mm. 



Area 22.2 cm. 



For normal adult Barred Plymouth Rock females the follow- 

 ing average values for comb size have been found : ** 



Mean length 50.80 ± .56 mm. 



Mean calculated height 10.57 — -^3 i^ni- 



Mean area 5.59 ^1= .17 cm. 



*These papers are (i) Studies on the Physiology of Reproduction in 

 the Domestic Fowl. III. A Case of Incomplete Hermaphroditism. 

 Biol. Bulletin, Vol. XVII, pp. 271-286, igog. (By R. Pearl and Maynie 

 R. Curtis). (2) A Triple Yolked Egg. Zool. Anzeiger, igio. (In 

 press). (By R. Pearl). 



*Made in accordance with the methods described by R. and JM. D. 

 Pearl in a paper "Data on Variation in the Comb of the Domestic Fowl," 

 Biometrika, Vol VI, pp. 421-423. 



**Pearl, R. and M. D., !oc. cit., p. 427. 



