REPORT ON THE POLYPLACOPHOEA. 19 



Lepidopleurus dallii, n. sp. (PI. I. fig. 6, PI. III. figs. 6a-6i). 



Habitat,— Station 310. January 10, 1876. Lat. 51° 27' 30" S., long. 74° 3' W. 400 

 fathoms. Blue mud. Bottom temperature 46°"5. 



Shell. — Evenly covered with closely set minute low tubercles, which give it a granular 

 appearance, with straight sides meeting at an angle of HO*. 



Anterior valve. — Coarsely granular, with twenty-six short radial rows of tubercles, 

 each row consisting of four or five tubercles, which diminish in size from the periphery 

 towards the apex ; the posterior row is the broadest, and is partially bifid. 



Intermediate valves. — Central area: jugum, coarsely granular; pleura, with about 

 twelve or thirteen distinct horizontal ridges. Lateral areas: granular, with three main 

 radiating rows of tubercles, the anterior and posterior often partially double. 



Posterior valve, — Remarkably flat, coarsely granular, with nineteen rows of three 

 tubercles each, of which the outermost is the largest. Umbo scarcely, if at all, raised 

 above the surface. Anterior border coarsely granular, with the granules passing into 

 oblique ridges on the pleura. 



Girdle. — Medium breadth, upper surface with smooth imbricating scales in oblique 

 rows, about seven or eight in a row, those nearest the shell being the smallest. 



Colour. — Greyish white. 



Size. — Length, 11 mm. ; breadth, 6 mm. ; height, about 3 mm. 



Gills. — Extending to about three-quarters the length of the foot, diverging posteriorly 

 and hidden by a slight swelling of the longitudinal band on the under surface of the 

 girdle ; about twenty-one in number, largest about the fifth from the posterior end, and 

 gradually diminishing in size anteriorly. 



I have associated this species with the name of my friend Mr W. H. Dall, of the 

 Smithsonian Institution, Washington, U.S.A. 



Lepidoradsia, Carpenter. 



Lepidoradsia australis (Sowerby). 



Chiton australis, Sowerby, Mag. Nat. Hist., 1840, p. 290, and Conch. Hhist., 1841, p/2, No. 19, 

 pi. cxxxix. fig. 46. 



„ evanidus, Sowerby, Conch. Illust., 1841, p. 3, No. 38, fig. 139. 



„ australis, Reeve, Conch. Icon., 1847, pi. ii. fig. 10. 

 Lophyrus australis, Angas, Proc. Zool. Soc. Lond., 1867, p. 221. 

 Lepidoradsia australis, Dall, Proc. U.S. Nat. Mus., 1878, pp. 79, 113, 115. 



Habitat. — Port Jackson. 6 to 1 5 fathoms. 



Australia, Eaine Island, Torres Strait (Cuming) ; Port Jackson, " common under 

 stones" (Angas). 



The collection includes several specimens of this common and well-known form. 



