POLYPLACOPHORA. 179 



Interior white, stained with brown. Anterior valve with 13, median 1, posterior 

 13 slits. 



Girdle with broad, flat, finely striated scales ; some scales do not show the sculpture, 

 but this is, I think, due to erosion. 



Length, when alive, about 15 millims. 



Hab. : Trincomalee (one specimen). 



Ischnochiton, sp. 

 A single specimen, from the Gulf of Manaar. 



Craspedochitou laqueatus (Sby). Plate I., fig. 7. 



Chiton laqueatus, Sby : 'P. Zool. Soc.,' 1841, p. 104. 



: Reeve, 'Conch. Icon.,' Plate XX., fig. 135. 



Craspedochitou laqueatus, Sby : Shuttlewoeth, 'Bern. Mittheil.,' 1853, p. 67; 

 Pilsbry, ' Man. Conch.,' vol. 14, p. 285, 



Angasia tetrica, Carpenter: Pilsbry, 'Man. Conch.,' vol. 14, p. 287. 



Hab. : South of Modragam Paar (Stn. LXIV.), 5 fathoms ; and North of the Gulf 

 of Manaar (Stn. LXIX), 7-13 fathoms (several specimens). 



I am unable to sever the Philippine shell from the Ceylon form described as 

 A. tetrica. The species has a varied generic history, as it forms the type of Craspedo- 

 chiton, Shuttlew., Angasia, Carpenter, nee White, and Phacellozona, Pilsbry. 



A single specimen from " Palk Bay, Februaxy, 1902," I refer here with some 

 doubt, as it is slightly more elevate, the posterior valve shows no trace of the 

 radiating lines, and there are other minor differences. 



Acanthochites penicillatus (Desh.) Plate I., fig. 2. 



Chiton penicillatus, Deshayes: 'Moll. Reunion,' p. 41, Plate VI., figs. 8-10. 



Chiton (Acanthochites) penicillatus, Desh. : Martens in Mobius' ' Reise Mauritius,' p. 300. 



Acanthochites penicillatus, Desh. : Pilsbry, 'Man. Conch.,' vol. 15, p. 15, Plate IV, fig. 84, 



Plate VIII., figs. 29, 30. 



Hab. : Gulf' of Manaar (two specimens). 



I identify the Ceylon with the Mauritian shell with a little doubt, as I know the 

 latter only from figures and descriptions. 



Tonicia pectinoides, n. sp. Plate I., fig. 1. 



Shell ovate, broad, elevated. Colour, reddish to yellowish-green. Lateral areas 

 well raised. The central areas and anterior portion of the posterior valve are 

 sculptured with longitudinal, broad, flattened riblets, the interstices marked by 



2 A 2 



