1 4 THE VOYAGE OF H.M.S. CHALLENGES. 



Habitat. — January 20, 1874. Boyal Sound, Kerguelen Island. Shore. 

 Kerguelen Island, on stones at low water (Dr Kidder). 



" H. t. latiore, curvata, olivaceo-fusca ; jugo planato ; niucrone subcentrali ] areis 

 baud definitis ; tota superficie sensim quincunxiter granulosa, granis satis extantibus. 



" Intus ; valva antica et postica conspicue laminata ; laminis aeutis, baud incisis, baud 

 regularibus, valde extantibus ; subgrundis spongiosis, minimis ; valvis centralibus et 

 postica laminis "suturalibus, triangularibus, maxime distantibus, extantibus, decliviter, 

 lateraliter, continuis ; sinu maximo, valde spongioso. 



Zona modica, baud expansa, sobda, leve ; sparsim minutissime lanuginata, ; poris 

 minutissimis, setuliferis ad suturas, et circ. iv. circumvalvas terminales sitis, instructa, 

 setulis miuimis, curtissimis. 



Animal, pede capiteque normalibus ; brancbiis majoribus posticis, utroque latere circiter 

 vi., medio pede tenus. Lon. 13 mm. Lat. 7 mm. Div. variante ad 130.°" 



The above description was written by Carpenter from two specimens sbortly before bis 

 deatb, and incorporated by Dall in bis report on tbe Mollusca collected by Dr Kidder at 

 Kergxielen Island, wbo accompanied tbe United States Transit of Venus Expedition, 

 1874-75. 



Tbe colour of tbe shell, in the single specimen collected by the Challenger Expedi- 

 tion, is of a uniform warm dark brown, and the girdle is chestnut brown, with a pale 

 crenulated border round the margin of the valves. In each of the dark triangular bays 

 between the valves is a small tuft of short white spicular scales, and there are six similar 

 tufts round the anterior border of tbe first valve. 



Tbe anterior and posterior valves and tbe lateral areas of the intermediate valves are 

 marked by concentric lines of growth, otherwise the latter are scarcely discernible. Tbe 

 jugum is very gently rounded, so that tbe pleura are slightly depressed. The unslit 

 insertion plate of the anterior and posterior valves is shown in PI. ii. figs. 4a, if. 



The girdle is thick and soft, with a few minute scattered scales. There is a distinct 

 fringe of reddish brown elongated striated scales round the margin. The scales forming 

 the tufts are stout, and white in colour. Carpenter describes tbe anterior tufts as about 

 four in number ; in my specimen there are six anterior tufts. Evidently Carpenter 

 was not quite satisfied on this point, as in all other Chitons which possess tufts, only 

 four are present ; and, consequently, that number might be expected to occur in this 

 species also. 



Tbe head lappets are rather large, and the anus is on a large rounded papilla. The 

 longitudinal band on the under side of the girdle (veil of Carpenter) is produced into 

 flaps at the posterior extremity. 



The gills form a short posterior row, and appear to be about six in number ; they 

 decrease-in size anteriorly. 



Length 9 mm. ; breadth 4 mm. j sides of valves meet at an angle of about 115°. 



