Ti:STACEA. U 



KLLA PELLCCIDA. Plate VII., Figs. 1 



Midi an irregular ellipse, in the <-i mi inference conical, one end 

 broader than the other, of a thin transparent horn colour, with, generally, 

 tour interrupted -ireaknof bright green radiating from tin- vertex t.. 

 tin- margin, with darker intermediate streaks : animal light brown : head 

 and body distinct ; two tapering tentamla, with a black eye at the ex.- 

 t'Tiial root of each. Tlic position of the head is under the vertex. <>r 

 toward the narrow jxirtion of the shell, und the Ixxly w covered by the 



I.T portion. The margin of the under surfarr i- eiivimncd by a 

 border of >hort filaments. Specimens have little exceeded half an inch 

 in length, and some, in favourable situations, are said to approach a 

 whole inch. 



Tliis creature occurs on the common Laminaria at low-water murk, 

 \\ hereon it seems to feed. Probably it also derives sustenance from th. 

 onlervsB, or other vegetation covering the rocks. 



It is certainly among the most delicate of it* race. 



I'l ATK VII. 



KH.. 1. Upper surface. 

 2. Under surface. 



PATELLA IM.ATA Tl,- Wated /,//////. Plate VII., Figs. 3, 4. 



As the smaller animals of this genus are most common, they have 

 been leas the subject of observation ; their reciprocal relations are uncer- 

 tain neither is it evident whether they grow much larger. 



The margin of the shell of the Waved Patella the eighth of an inch 



in diameter, is somewhat of an elliptical form. Vertex white, with waving 



lines radiating down to the margin. The animal occupying the shell 



- on tin- Millepora. Perhaps the specimen represented may be young. 



1'l.ATK VII 



Fi.. :;. PaitUa mdata, enlarged. 



;. I' 



