i86 



Shell Life 



brown marked with streaks and specks of white or 

 yellow. There is a fairly broad girdle of dusky 

 brown fringed with very short yellowish 

 spines. The head-plate has 8 notches, 

 the tail-plate 9, and the intervening 

 plates 2 each. It occurs among stones 

 and weeds a little beyond low water, 

 but not south of Yorkshire. 



Through the Limpets we become ac- 

 quainted with the order Prosobranchiata, 

 which includes the great majority of 

 native Gasteropods. The name signifies 

 that in this order the plume-like branchiae or re- 

 spiratory organs are usually placed in front of the 

 heart. The animals have a distinct head, which is 

 furnished with a pair of tentacles and a pair of eyes. 

 They are mostly marine animals, protected by a shell 

 and mostly by an operculum ; the sexes are separate. 

 It is divided into two sub-orders, and these again into 

 sections. The species described in this chapter belong 

 to the sub-order Diotocardia, most of the animals 

 comprising it having two auricles to the heart, but 

 the Limpets are exceptional in that they possess only 

 one auricle and one ventricle. 



The Tortoiseshell Limpet {Amnesia 

 testadinalis) has a conical but depressed 

 shell, with growth lines fairly strong, 

 and with fine scratch - like lines both 

 i-adiating and concentric. It is rather 

 thin, with a dull surface, the ground 

 colour grey, irregularly marked with 

 reddish brown, sometimes with white in addition. The 

 interior is polished, except the broad, bevelled margin, 



