Fine structure of the canine tapetum lucidum.

The structure of the canine tapetum lucidum appears to be basically similar to that described in some other carnivores, but specific distinctions are present. The reflecting rodlets of the dog are similar in their dimensions to those of the cat, but they are more closely packed, resulting in a unique value for the wavelength of maximal reflectance. In addition, the rodlets are less precisely orientated, as compared to those of the cat, a condition which appears to result in a less efficient reflectance from the dog tapetum. It has also been shown that the dog does not possess a retinal tapetum lucidum, as had previously been suggested.