The finished product is in sight now as more layers of black go down. I refer constantly to the photo in order to emphasize detail in shading. The eyes are starting to take shape, but I find that I am fiddling with the right eye. As with the nose, I think I am having trouble because her fur is very dark in the photo and it is difficult to make out fine details. Also, what I thought was white in Cya's fur is, I think now, highlights from the light that is coming in from the right so I will tone them down a bit with grey. The nose is looking more natural since I darkened the fur around it...as they say, everything is relevant.
From here on in, it is a matter of tweaking, a bit of lifting and a bit of deepening shades. Often it is a case of "when do I stop". The image below is "finished" but I will leave it overnight and look at it with fresh eyes tomorrow. I am pretty happy with the result and going back in to make little changes can sometimes turn out wrong.
Okay, so on returning to the painting in the morning, I could see one or two small things that I could change that I think would improve it. Basically, it was just a matter of darkening up the right eye a tad and deepening the shadows on the left.