DES C R IPTIO N. 189 



Specimen reddish white with a pale brown cloud 

 and mark on the columellar side, and two brown 

 bands upon the base ; aperture white, with seven 

 teeth, two nearest the exterior margin bent; outer 

 lip margined, acute; — whorls six, smooth. 



Inhabits Pernambuco. 



PLATE XXVIII. 



Fig. 1. Chiton porosus. 



Shell 8-valved, carinate, valves with a tooth on 

 each side, covered entirely with the marginal mem- 

 brane. 



Specimen pale olive above, sides brown ; cori- 

 aceous covering cinereous or pale brown, tomen- 

 tous ; perforated over the back of each valve with 

 a small slit and two tubular pores, one on each 

 side ; over the anterior valve four pores ; valves 

 finely striate and irregularly granulate ; posterior 

 valve indented in the margin; lateral triangles 

 marked by an obsolete fold, and terminated by a 

 small, sharp, tooth-like process. 



Habitat uncertain, but probably New South 

 Wales. 



