UNIVALVE MOLLUSC A. 



431 



flattened, covered with angular wrinkles, and dentate on the edge. 

 It is of a spotted green outside and of a fine glossy blue within. 



Other very elegant species are Patella umbella (Fig. 212), from 

 the African coast ; Patella granatina (Fig. 213), the ruby-eyed 

 limpet from the Antilles; Patella barbata, the bearded limpet 



Figs. 215 and 216. Patella longicosta (Lamarck). 



(Fig. 214); and the long spined Limpet, Patella longicosta (Figs. 

 215 and 216). 



The fourth family, Calyptr&idce, of which the genera Pileopsis and 

 Calyptrcea may serve as a type, was classed by the older conchologists 

 with Patellidce. Pileopsis hungariciis, the Hungarian bonnet shell, is 

 rather abundant on some parts of the British coast. 



The fifth family, Fissurellidce, contains the 

 genera Parmophorus, the duck's-bill limpet of 

 Australia, and Fissurella, the key-hole limpet, 

 which is remarkable for the opening of the 

 apex of the shell. 



The sixth family, Haliotidce, contains Ian 

 thina, Stissurella, and Haliotis. 



The attention of naturalists has long been 

 directed to a curious mollusc known under 

 the name of lanthina communis (Fig. 217); 

 its body is globular, and it presents an opening in front without con- 

 tracting itself in order to form the head, which is long and trumpet- 

 shaped, terminating in a large buccal opening, furnished with horny 

 plates, and covered with little hooks ; and two conical tentacles, 

 slightly contracted, but very distinct, each bearing at their external 

 base a long peduncle. The foot is short, oval, divided into two 

 parts : the anterior, concave and cup-shaped ; the posterior, flat and 



Fig. 217. 



lanthina communis 

 (Lamarck). 



