162 SYSTEMATIC ARRANGEMENT 



The Trochi have only one auricle and one branchial leaf, a heart not 

 in contact with the intestine, and the rectum far removed from it, at 

 the front of the right side. An operculum. — Clark. 



Ear-shells (Haliotis) are found as far north as Kamtschatka : one 

 lives in deep water near Fort Simpson, Columbia. — Sir George Simp- 

 son. And as far south as New Zealand, where they are used for 

 food. 



2. Padollus. 



Shell ear-shaped, subcircular, with two parallel spiral ridges ; the 

 outer perforated in front as in Haliotis ; the other simple. 



1. P. tricostalis. 



b. Foot very large ; hinder part much produced, and furnished 

 with a deep longitudinal groove. Shell polished. 



3. Teinotis. 



Shell depressed, elongate, ear-shaped, polished, with a single spiral 

 ridge pierced with holes in front ; spire small ; aperture much longer 

 than broad. Foot very large, thick, much produced behind, and 

 furnished with a deep longitudinal groove above ; lateral fringe pro- 

 duced to the end of the groove. 



1 . T. Asinina, Adams, Gen. Moll. 442. t. 50. f. 6. 



Suborder III. Dicranobranchia. 



Gills, two symmetrical plumes on the back of the neck, with the 

 vent between them. Body and shell symmetrical, Central teeth 

 unequal, middle one small, similar, outer lateral large, dissimilar. 

 Sides of the foot tubercular, obscurely bearded on its upper edge. 

 Eyes slightly tubercled or sessile. Operculum none (p. 160). 



Fam. IX. FISSURELLHLE. 



Foot dilated ; upper side with a series of short tentacles. Body 

 and shell short, broad, conic. Gills two, separate, symmetrical. 



a. Vent anterior. Shell external, or partly covered with the 

 mantle, entire, truncated in front. 



1. Scutus. 



Shell depressed, oblong, smooth or striated, truncated in front ; 

 edge smooth. 



1. S. Unguis. Parmophorus australis, Quoy, t. 111. 



2. S. elegans. P. australis, Ruppell, t. 43*. f. 6, 7. 



