THE ASS'S EAR. 



397 



or " umbilicus " as it is technically called, is seen to be hollow, and looks somewhat 

 like that of the solarium. 



The animal has no head lobes, but the sides are furnished with lobes and cirrhi, i.e. 

 the tentacular projections already mentioned. The Dolphin-shells- prefer the shallow 

 water, and at low tide may be picked by hand off the reefs. The color of the Dolphin- 

 sh-jll is purplish tending to black, and the aperture is pearly. 



IN the next family of molluscs, the shell assumes a very remarkable shape, for 

 although it is constructed on the spiral principle, the spire is so very small and the 

 aperture so very large that many persons would take it for one of the bivalves. Most of 

 these shells are shaped after the form of the human ear, which has earned for them the title 

 of Haliotidae, i.e. Sea-ears. The outer lip is either notched at the edge, or perforated 

 with a series of oval holes, and thegeneral substance of the shell is pearly, and colored 

 with tints, vivid as those of the rainbow, and refulgent as those of the humming-bird's 



NILOTIC TOP.-Trochus Nllotlcus. 



DOLPHIN-SHELL.-De/pA/ou/a lacialata. 



throat. The outer angle of the shell is perforated by a series of oblong holes, which are 

 generally filled up as they approach the spine and at last are wholly obliterated. Some- 

 times, as in a very fine specimen now before me, several of these perforations coalesce, so 

 as to form a long rounded slit, nearly two inches in length. The animal has slender and 

 conical tentacles, with the eyes set on footstalks at their outer bases ; and as the 

 operculum which would be needed to close so large a mouth would be of unwieldy 

 dimensions, that organ is almost rudimentary, and appears to serve no practical purpose. 



The Ass's EAR is one of the larger species of the genus Haliotis, and is one of the 

 most beautiful among the shells. Even when rough and unpolished, just as it appears 

 after the removal of the animal, the rich iridescence of its interior is almost dazzling in 

 the intense brilliancy of its coloring ; and when, by the use of acids, the rough outer coat 

 is removed and the nacreous substance of the shell exposed, there is hardly any marine 

 production that approaches it and none that surpasses it in beauty. 



This is a very useful shell to the manufacturer, its thick solid substance, with its lovely 

 iridescence, rendering it well adaptable for the construction of buttons and similar 



