Sloughing by Lamellaria perspicua

In March 2011, I collected five specimens of Lamellaria perspicua from the Menai Strait for photography. To keep the water fresh and slow down their metabolism until they could be released, they were kept in a refrigerator. After two days, a slough of the outer epithelium of one of them was found in their container (fig. 1).

I am unsure which specimen it came from, but suspect it was the lilac coloured individual in figure 2. The slough clearly shows a long indentation at the anterior, representing the uncurled siphon, and an indentation that corresponds with a tubercle on the live animal.

The lilac specimen has far fewer tubercles and is consequently more translucent than is usual in the species. The internal shell and its spire can be discerned through the mantle.

Has any reader observed sloughing in this species? It might be a regular event associated with growth or a reaction to adverse conditions. I incline towards the former suggestion as, if it were due to external conditions, I would have expected the other specimens to slough also. All five lived in apparent good health until release three weeks later.

_{figure 1: Sloughed epithelium of Lamellaria perspicua.}

_{figure 2: Lilac specimen of Lamellaria perspicua with unusually few tubercles.}

_{figure 3: Lamellaria perspicua with normal number of tubercles.}