In the typical ampullacea the epidermis is thin yellowish, and in perfect, fresh specimens covered with minute, very short cilia, caused by the elevation of minute threads of the epidermis at the intersection of the crowded fine revolving striae which cover the whorl, with the lines of growth. In some apparently perfect specimens, however, the epidermis appears perfectly smooth and even polished. In the present variety, however, the epidermis is much thicker and stronger, almost pilose, though preserving the same general characters. In both the suture is canaliculated.

Sitka, Alaska Territory, in abundance, Dall and Bischoff.

With regard to the V. ampullacea, a very remarkable fact may be mentioned. The majority of the individuals are without opercula, even without a trace of the pad-like gland or area from which the operculum is secreted. About ten per cent, of the individuals which I have examined had traces of this gland or area, marked by its smooth and rather whitish surface on the granulous dark slate colored foot. About fifteen per cent, had well developed opercula in the proper posi¬tion. I have ascertained the same to be the case with regard to the typical form, from alcoholic specimens, collected by Dr. Stimpson in Behring Strait. There is no mistake about this, strange as it may and must appear, that different individuals of the same species are indifferently operculate or inoperculate.