562 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.49. 



ing other moUusks in which, the shell had attained a certain degree 

 of solidity, and conclude that they confine their predatory work to 

 animals and substances only moderately well protected from such 

 attacks. 



These animals prefer a rocky habitat, especially one weU covered 

 with fucus, underneath which they remain concealed, and they are 

 rarely seen exposed to the glare of the sun. They occur from the 

 vicinity of high-water mark to a depth of several feet below low 

 water, and have been dredged from a considerably greater depth, in 

 one case in over 60 fathoms. But these specimens are usually not 

 living, and their presence at such a depth can be ascribed to accident, 

 such as the disgorging of a recently swallowed shell by a fish, or wash- 

 ing from their actual situs by the surf. Some species, Hke N. lamellosa, 

 appear to frequent banks of rock or coarse gravel which are rarely 

 uncovered by the tide and yet are favorite haunts of barnacles, and 

 of oysters, anomias, and other rough bivalves upon whose yoimg the 

 Nucella feeds. The smaller species, like emarginata, seem to prefer 

 the rocks covered with bladder-weed along shore. 



I have not observed Nucella among the shells in the aboriginal 

 middens of the Alaskan coast, nor are they eaten by the natives at 

 the present time, although abundant enough to form an article of 

 food. Jeffreys states that the British species is found in some of the 

 Pictish middens, and that it is destructive to mussels and hmpets, 

 but on the Alaskan coast during many years collecting I have never 

 found a drilled hmpet shell or a Nucella attacking any but very young 

 mussels. 



The ovicapsules are abundant in early spring and, hke those of the 

 tribe elsewhere, are elongate slender yoUowish vasehke objects of a 

 parchmentlike texture, with a flat circular top, and are mounted on 

 slender cyhndrical peduncles in groups on rocks or dead bivalves. 



The young, of which a considerable number occur in a single cap- 

 sule, are cannibals, the weaker ones being devoured by their brethren 

 while still in the capsule, from which the survivors emerge at the top, 

 leaving the vase unsealed. The adults also browse on the capsules, 

 which are easily cut through by the sharp teeth of the radula. 



Like the other species, these produce a purple dye, which I tested 

 on an old handkerchief. It gave a dull purple color, which faded 

 badly; but I afterwards learned that it could be made permanent by 

 the addition of lemon juice, which is used with the purple of the 

 tropical species by the natives of Central America and Peru. How- 

 ever, I have never seen any articles dyed with this substance which 

 had any briUiancy or attractiveness of tint. If the classical descrip- 

 tions of the Tyrian dye are correct, the American purple can not 

 compete with it. 



Jeffreys says that the fluid contained in the N. lapUlus ovicapsules 

 is also purpuriferous (besides having a disagreeable peppery taste), 



