242 VELUTINID.E. 



to 150 f. ; United States (Gould and others) ; Canada 

 (D'Urban) ; North Pacific (Stimpson and P. Car- 

 penter) . 



" The animal discharges a very copious and tenaci- 

 ous clear white slime/' Clark. According to Fabricius 

 this secretion is frothy (like that of Helix aspersa) , and 

 serves the Velutina for concealment. Its locomotion is 

 slow; and its sedentary habit may be presumed from 

 Foraminifera being frequently attached to the shell. 

 This presumption, however, is not quite tantamount to 

 a fact, because (as Mr. Alder reminds me) Foraminifera 

 and Polyzoa are found on the carapace and legs of some 

 of the smaller crabs, which are anything but stationary 

 animals. Greenland specimens of V. Icevigata are very 

 much larger and thicker than ours. Extremely young 

 shells have a small umbilical cavity. 



The Helix Iczmgata of Linne appears to be a lost 

 species. It is described as of the size of a pea, trans- 

 parent, very smooth, nearly oval, and glossy, with scarcely 

 any umbilicus. He placed it next to Limnaea auricularia ; 

 no habitat is given. Pennant appears therefore to have 

 considered the present species a freshwater kind. His 

 description and figure almost suffice to identify our 

 shell; but were it not so, it would be inexpedient to 

 change the familiar specific name of Icevigata. It is 

 the Bulla velutina, Miiller, Helix halioto'ides, Fabricius 

 (not of Miiller, nor H. halioto'idea of Linne), V. capu- 

 lo'idea, De Blainville, V. vulgaris, Fleming, V. striata, 

 Macgillivray, V. rupicola, Conrad, Galericulum ova- 

 turn, Brown, V. Mulleri, Deshayes, and V. halioto'idea, 

 Stimpson. 



V. undata of J. Smith (V. zonata, Gould) is fossil in 

 the Clyde beds, the Mammalian Crag at Bramerton, 

 Uddevalla, and Canada ; it inhabits the arctic seas of 



