1. Carcasses of nineteen fat lambs (from six ewes and thirteen wethers weighing from 29 to 841b., aged from 78 to 365 days, all from the Suffolk breed and all fed in pens with no grazing) have been dissected into six joints, namely neck, thorax, loin, pelvis, shoulder (including shank), and leg (including shin). The subcutaneous and intermuscular fatty tissues and the muscular tissues have been dissected from each joint and analysed for fat. The iodine number of each sample of fat has been determined.

2. The average percentage of fat in the fatty tissues of the carcass ranged from 71·9 to 87·8 and the average iodine numbers from 43·6 to 56·1. With the muscular tissues these figures were from 4·8 to 11·1 and iodine numbers from 51·5 to 61·7.

3. The extreme ranges found in the subcutaneous fatty tissue of the joints were from 63·0 to 91·6 for percentage of fat and from 43·7 to 59·3 for iodine number. For the intermuscular fatty tissue these ranges were from 52·0 to 88·4 for fat and from 41·7 to 58·5 for iodine number. The kidney fat extended this range up to 95·7 for fat and down to 36·4 for iodine number. With the muscular tissue of the joints the ranges were from 2·7 to 17·3 for fat and from 48·3 to 65·0 for iodine number. The rectus femoris muscle extended this range down to 1·8 for fat and up to 66·2 for iodine number.