DOMINANCE OF CHARACTERISTICS IN POULTRY. 139 
The second table is arranged to test de Vries’s hypothesis of 
dominance of patent over latent characteristics. As not all of the 
preceding characters can be placed in these two categories, this list differs 
from the last. 
Characteristic | Patent Condition Latent Condition 
1. Nasal process of pre- | 
maxillary Narrow nostril High nostril 
2. Cerebral closure Plain skull Cerebral hernia 
3. Crest Present Absent 
4. Complete development 
of feather Non-silkiness Silkiness 
5. Plumage pigment Black and red White (usually) 
6. Shafting Present Absent 
7 
. Pencilling Present Absent 
This table shows that of the foregoing seven characters six are 
dominant in the patent condition. The exceptional case of white 
pigment is not universally dominant. The resulé indicates that de 
Vries’s law is a valid one where the allelomorphs can be classified as 
patent and latent respectively. The law has, however, this plain limit 
to its applicability. 
A more general expression of the law of dominance in poultry is this : 
a progressive variation, one which means a further stage in ontogeny 
(whether novel or ancient, and without reference to latency or patency), 
will be dominant; a variation that is due to abbreviation of the onto- 
genic process, which depends on something haying dropped out, will be 
recessive. The following table shows this relation : 
Characteristic | Progressive Condition Arrested Condition 
1,9! { Pea Geer 
Bf comb | Rose Single 
3. Nasal process of pre- Developed; narrow nos- Undeveloped; wide nos- 
maxillary | tril tril 
4. Cerebral closure Perfect; plain skull Imperfect ; hernia 
5. Crest Present Absent 
6. ’ | { Typical ; lain Embryonic ; silk 
7. } Feather-form | Huseled ae Plein’ : 
8. Muffling Present Absent 
9. Skin colour | Pigmented; black | White 
10. Iris colour Pigmented; black Red 
11. Plumage colour: Pigmented White (usually) 
12. Melanic pigmentation Melanism ; ; wholly black Red and black pigmented 
13. Shafting | Present | Absent 
14. Pencilling | Present | Absent 
Of the foregoing fourteen characters thirteen have the more progressive 
condition of the characteristic dominant. ‘The exception is again plumage 
colour, which is, as stated, not always an exception. 
To sum up, I think the evidence warrants the conclusion that, 
in poultry, dominance of a characteristic in hybridisation is usually 
determined by the same causes as determine the appearance in the race of 
& progressive Variation. 
