No. 626] SHORTER ARTICLES AND DISCUSSIOX 



267 



the pet-stoek journals for information about Siamese cat crosses 

 A single reply has just come to hand, but from an authoritative 

 source. A doctor, who prefers to remain anonymous, resident 

 in an extensive institution in England and a fancier of Siamese 

 cats, has employed his leisure, and the unusual opportunities 

 afforded by his position, in studying the genetic behavior of 

 Siamese cats in crosses with other varieties. He regards as 

 characteristics of the Siamese breed a peculiar quality of voice 

 and "cross-eyes," which characters often are seen in first 

 generation crosses and so would seem to be inclined to domi- 

 nance. But the distinctive Siamese color, he states, is never 

 seen in individuals, "although quite a number show a mid- 

 way color. At a glance you would say they were black, but on 

 more careful examination you see they are near the color of the 

 Siamese ears, seal brown. Most first crosses in my experience 

 are black or seal, but some tortoise shell, or tortoise shell and 

 white, or black and white. ' ' These statements indicate the usual 

 behavior of yellow and of white-spotting in cat crosses. (See 

 Whiting, 1918.) The Siamese color is evidently an independ- 

 ent character incompletely recessive in F^. The doctor contin- 

 ues his account with a brief statement concerning a back cross 

 of Fi with pure Siamese. "I have a first cross female, black 

 seal color, marked cross eyes, Siamese voice. She has been twice 

 mated with a pure Siamese male. In her first litter she had two 

 pure Siamese, perfect Siamese color. Unfortunately both died 

 of distemper when about three months old. Her second mating 

 resulted in one pure Siamese which is still alive. It is about 

 five months old and is perfect in all Siamese points and fit to 

 win [at shows]." Presumably the same sort of back-cross mat- 

 ings as these would produce also kittens similar to the F^ mother 

 in color character, although no mention is made of them in these 

 notes. The information given suffices to show the segregation 

 of Siamese color as a recessive character in generations later 

 than Fj. The doctor confirms the observation of others as to 

 the deficient pigmentation of the eye, a point of resemblance 

 with allelomorphs of true albinism, as seen, for example, in red- 

 eyed guinea-pigs (Castle and Wright), and in ruby-eyed rats 

 (Whiting). He says: "The reflex which the Siamese eat shows 

 in the dark is worth notice. It looks l)loo<l rod and must he due 

 to absence of pigment in the retiiin."' A furthtM- point of re- 

 semblance with albinism is its distiru-tiuss fi'om dilution as seen 

 in "blue" varieties. The doctor speaks of having produced 



