For anyone interested:
The 6 horizontal circles are labeled A to F, the six vertical circles G to L. The image was taken from the Star Fleet Medical Reference Manual, written by Geoffrey Mandel and illustrated by Doug Drexler.
The book identifies the 12 letters as:
A - Optikos, B - Reflector, C - Gullet, D - Brain, E - Pulmos, F - Matrix Gland, G - Proboscis, H - Heart, I - Viscera, J - Nephros, K - Ovary, L - Crop
- I will add this info to a background section Capricorn 08:59, 17 July 2007 (UTC)