MOLLUSCA. 



III.-AMPHINEURA. 



By EDGAR A. SMITH, I.S.O. 



CH^ETOPLEURA MIRANDA.* 

 (PI. II., figs. 13-13g.) 



ANIMAL elongate, more than twice as long as broad ; valves thin, acutely keeled 

 along the middle, flatly sloping on each side, standing erect posteriorly, one above the 

 other; anterior valve (fig. 13b) with eight to ten slender radiating costse, slender above, 

 and gradually thickening towards their extremity, radiately striate or sulcate between 

 the ribs; medium valves (fig. 13c) with a single costa on each side, the rest of their 

 surface being radiately sulcate or striated and marked with fine lines of growth ; the 

 posterior valve (fig. 13d) has the mucro behind the centre, and, besides the radiating 

 sulcation, exhibits one or two more conspicuous sulci diverging laterally from the apex ; 

 the girdle is clay-coloured, rather broad, fleshy, closely beset with short spicules ; colour 

 of valves dirty whitish, excepting the third and seventh, which are more or less 

 reddish ; insertion plates thin, that of front valve with nine fine, short slits corres- 

 ponding to the external ribs (fig. 13e) ; intermediate valves (fig. 13f) with a single 

 lateral slit, posterior valve (fig. 13g) with six slits. 



Length (including girdle), 55 millim. ; diam., 25 ; height from sole of foot to the 

 apex of the fourth valve, 12 millim. 



Winter Quarters, Holes 6, 10. In 125-130 fathoms. 



Three specimens of this interesting chiton were obtained, all agreeing in coloura- 

 tion, which is remarkable, as only the third and seventh valves are stained with red, 

 the rest being dirty whitish. The gills extend about two-thirds along the side of the 

 foot. 



* Mr. Smith has this morning received Dr. J. Thiele's report on the Chitons of the " deutscher Tiefsee 

 Expedition," in which (vol. ix., p. 332) this species is noted as Notochiton [g.n.] mirandus; the locality cited 

 (Bouvet Island) shows the wide distribution of the species. ED., Oct. 22, 1906. 



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