RE: Lobster claws.

I have been recently involved in a study of prawns (shrimps) .................these prawns were approx. 30 g each (!) and after fixation in Davidson's for 72 hours, I found the cuticle had softened sufficiently well (due to the acetic acid) to permit excellent sections at 3 microns to be cut. The prawns were fixed by perfusion into the living prawn and I have to say when the fixation was not well done, I had real problems cutting decent sections. A minimum of 10 x their volume is required and if the size is large (as I guess they would be in your case) ie, greater than 12g, they should be transversely slit once at the abdomen/cephalothorax junction. If they are not to be processed immediately, then you can store them in 50% alcohol. As I say, I had no problems in cutting good, 3 micron sections. I did, however, have problems in cutting sections of Tilapia fish recently. The covering on these fish are tough and although fixation/decalcification was carried out in 10%NBF/Gooding and Stewart's fluid, I softened the blocks in 4% phenol prior to processing for one hour and then in fabric conditioner overnight after I had trimmed the processed blocks. The sections cut like a dream and I was very pleased with the results. Without using the phenol/fabric conditioner, the blocks were almost impossible to cut and the sections I did get were awful!