134 

 CHAPTER XXXIV. 



OF THE HALIOTIS. GENUS XXXI. 



HALIOTIS. 



"Animal a Z/iwax. Shell ear-shaped, spreading; spire close to the side, 

 the disk perforated by a row of holes." — Linn. 



Xhis genus would be very distinct from every other, if it were 

 not for two shells that are placed among the Helices by Lin- 

 nseus, and which perhaps it would be better to remove ; viz. 

 Helix haliotoidea and jierspicua. 



The Helix haliotoidea should rather be placed next to tlie 

 Bulla aperta, if the animal is at all to be attended to. Helix 

 perspicua appears from its texture as well as from its form to 

 be truly an imperforate Haliotis : as this appears to be the only 

 imperforate one known to Linnaeus, it is not surprising that he 

 should hesitate about placing it with the perforated Haliotidea, 

 as he remarks that " the inside of the spire appears like a 

 Haliotis, but it is not perforated." But now that two or three 

 more imperforate species are known, it may with great pro- 

 priety be placed in this genus. 



These shells are very open and flat ; they have no column 

 or pillar, but the inside of the spire is open to the top ; they 

 do not inclose the animal, but only cover its back ; the spire 

 is very small, scarcely elevated above the other part of the 



