48 AMPHINEURA. [Polyplacophora. 



nodules, interspersed with eyes. Girdle narrow, leathery, with narrow 

 white stripes below the sutures. Colour light pink over the jugum. 

 minutely dotted with white, margined by rows of triangular white 

 spots ; central and lateral areas reddish-brown, variegated with white 

 on some of the intermediate valves. Interior reddish-brown ; anterior 

 valve with 10 irregularly spaced slits ; teeth pectinate ; intermediate 

 valves with 1 slit on each side ; posterior valve with a low, smooth, 

 and rounded callus. 



Length, 17 mm. ; breadth, 7 mm. Divergence, 70. 



Type in the cabinet of Miss Mestayer, Wellington. 



Hob. Foveaux Strait, in 18 fathoms, one specimen (Captain 

 Bollons), type ; Guard's Bank, Pelorus Sound (Captain Bollons). 



Remark. This species is nearly allied to 0. rugulosus, Angas, from 

 Port Jackson, which, however, is much more depressed, the divergence 

 being 125. According to Thiele, this is 0. marmoratus, Wissel, 1904 : 

 see Appendix. 



2. Onithochiton semisculptus, Pilsbry, 1893. Plate 2, fig. 23. 



Onithochiton semisculptus, Pilsbry. Man. Conch. (1). xiv, 247, pi. 55, f. 10, 

 11 : J. Mai., xii, 71 : Wissel, Zool. Jahrb., xx, 658, pi. 21, f. 64; pi. 24, 

 f. 65, 66 (anatomy). 



Shell oblong, elevated, subaiigular, olive-green, white and brown, 

 concentrically banded and sometimes longitudinally striped. Anterior 

 valve with numerous close radiate riblets, distinct near the margin ; 

 anterior half with small black eyes irregularly scattered about. In- 

 termediate valves with a low keel on the jugum, beaked ; central area 

 smooth, shining ; lateral areas slightly raised, indistinctly separated 

 from the pleura, with fine and close radiate riblets, which are more or 

 less distinctly granose, their number varying from about 12 to 20 : 

 front of each lateral area with a small number of eyes. Posterior 

 valve convex, smooth ; mucro terminal. Girdle rather broad, buff with 

 numerous minute brown dots, brown when dry. Colour dark olive- 

 green, with snowy angular lines and dots on the lateral areas, and 

 closer more regular transverse lines on central areas ; sometimes 

 beautifully ornamented with white and brown longitudinal streaks 

 of various width. Interior white or light blue ; anterior valve with 

 8 slits, median valves with 1 slit, on each side ; teeth very blunt and 

 strongly pectinated ; sinus rather broad, denticulate ; sutural lamina 1 

 broadly rounded, slightly higher near the sinus. 



Length, 27-5 mm. ; breadth, 16 mm. (type) : divergence, 95. A 

 specimen in my collection : Length, 46 mm. ; breadth, 25 mm. 



Type in Mus. Acad. Nat. Sci., Philadelphia. 



#a&. Chatham Islands (H. B. Kirk). 



Remark. It is distinguished from all other known species by the 

 sculpture of the lateral areas. 



