52 FEBRUARY. 



deep water off these coasts, but rarely found by the 

 shore collector, though it does occasionally venture to 

 peep at daylight at the verge of extreme low-tide. It 

 is the Slit Limpet, 1 which by the older naturalists was 

 placed in close alliance with the Limpets proper, as if 

 a member of the same family. They were, however, 

 deceived by paying too exclusive attention to the form 

 of the shell, which is a cone, somewhat rounded, and 

 nearly simple, the summit being slightly turned over in 

 a backward direction. The margin of the shell is deli- 

 cately notched, the points being the extremities of the 

 radiating ridges ; for the entire surface is covered with 

 reticulations, one series of alternate furrows and ridges 

 proceeding from the summit to the margin, and another 

 series crossing these at right angles, running round the 

 shell parallel with the margin. The animal has its sides 

 ornamented with short fleshy processes, and possesses 

 two symmetrical gill-plumes, one on each side. It is 

 rather attractive in appearance, but I cannot tell you 

 anything of its manners ; for though I have kept speci- 

 mens in the aquarium, they are so habitually sluggish, 

 and so reluctant to allow one a peep beneath the edge 

 of the jealous shell, that I could learn nothing about 

 their ways ; if indeed they have any. 



1 Emarginula reticulata, of which a figure appears in 'the right-hand 

 corner of Plate v. 



