STUDIES ON THE PHYSIOLOGY OF REPRODUC-TION IN THE DOMESTIC FOWL. III. A CASE OF INCOMPLETE RAYMOND PEARL AND MAYNIE R. CURTIS ORIGIN AND GENERAL CHARACTER OF SPECIMEN. 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 paper. This bird was a Barred Plymouth Rock and when adult presented externally the general appearance of a normal hen of this variety, so far as the charac-ters body form and plumage color were concerned (cf. Plate I.). As the photograph in Plate I. 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 2 of the comb of this bird were as follows : Length ........................................................... 88.4 mm. Calculated height .............................................. 25.1 mm. Area ............................................................... 22.2 cm. 2 For normal adult Barred Plymouth Rock females the follow-ing average values for comb size have been found : 3 Mean length ............................................ 50.80 .56 mm. " calculated height ............................. 10.57^.23 " " area ............................................. 5.59 .!7cm. 2 It is evident from these figures that the comb in this specimen greatly exceeds in size the average for females of the variety. 1 Papers from the Biological Laboratory of the Maine Agricultural Experiment Station, No. 13. 2 Made in accordance with the methods described by R. and M. D. Pearl in a paper "Data on Variation in the Comb of the Domestic Fowl," Biotnctrika, Vol. VI., pp. 421-423. 3 Pearl, R. and M. D., loc. cit., p. 427. 271
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