310 GASTROPODA. [Pectintbranchia. 



concave, bent to the left on reaching the canal. Inner lip broad, 

 extending far beyond the columella, with a sharp and free edge, nar- 

 rowed to a point below, and spread thinly over the parietal wall. 

 Operculum light brown, horny, obliquely striate, nucleus apical. 



Diameter, 62 mm. ; height, 103 mm Angle of spire, 62. 



Dentition. Troschel. Das Gebiss d. Schnecken, pi. 20, f. 11 ; Man. 

 Conch. (1), iii, pi. 2, f. 12. 



Hob. Throughout New Zealand and at the Chatham Islands, 

 usually in 10 to 20 fathoms ; Auckland Islands. 



The type is from the Cape of Good Hope. The species has been 

 recorded from Tasmania, Australia, St. Paul and Amsterdam, Tristan 

 da Cunha Islands, Natal, Cape Colony, and Chile. 



The description is drawn up from New Zealand specimens. 



Remarks. Von Martens is inclined to take R. arc/us and R. vcxillum 

 as distinct species (Deutsche Tiefsee Exped., Gastropoden, 1903, p. 41). 

 Its distribution is similar to that of Phalium pyrum ; but its presence 

 in the Antarctic region, and the palreontological facts, prove that it 

 has been spreading towards the Antarctic from the Cape of Good 

 Hope. (Von Ihering.) 



2. Argobuccinum australasia, Perry, 1811. Plate 43, fig. 5. 



Biplex australasia, Perry, " Conchology,' 1 1811, pi. 4, f. 2,4. Ranella leu- 

 costoma, Lamarck, A.s.V., vii, 1822, 150. Triton leucostomuin, Q. & G., 

 Voy. Astrol., ii, 546, pi. 40, f. 3-5. Ranella leucostoma, Lam., Conch. 

 Icon., ii, pi. 1, f. 4. R. (Argobuccinum.} leucostoma, Lam. : Watson, 

 Chall. Rep., xv, 401. Lotorium (Argobuccinum} leucostoma, Lam. : 

 Pritchard and Gatliff, P.R.S. Vic., x (n.s.), 268. Gyrineum australasia, 

 Perry : Kesteven, P.L.S. N.S.W., 1901, 713, pi. 36, f. 1 (protoconch). 

 Apollo australasia, Perry, Index, 75. Biplex australasia, Perry = Ranella 

 leucostoma, Lam. : Hed'ley, P.L.S. N.S.W., 1902, 26. Ranella leucostoma, 

 Lam., Man. Conch. (1), iii, 42, pi. 23, f. 53, 54. 



Shell of medium size, fusiform, shouldered, with a nodulous keel, 

 varices subdiscontinuous. Sculpture consisting of subequal spiral 

 threads, with finer ones in the interspaces, crossed by very close and 

 fine growth-lines ; carina of the shoulder, and usually 1 or 2 cinguli 

 towards the base, ornamented with strong rounded nodules, 5 to 6 

 between the varices, which are not quite continuous, elevated and 

 rounded. Colour reddish-brown, varices banded with white and 

 dark brown ; the margin below the suture and the nodulous cinguli 

 are of darker colour ; aperture white. Epidermis olive, velvety. 

 Spire elevated conical, gradate, but little higher than the aperture ; 

 outlines straight. Protoconch of about 5 smooth and convex whorls. 

 Whorls 10 to 11, first rather slowly increasing, the sloping shoulder 

 moderately concave, straight below the carina ; base flattish. Suture 

 impressed, uneven, and wavy. Aperture slightly oblique, ovate, with 

 an inner channel above, produced into a short open and slightly re- 

 curved canal below. Outer Up with a thick varix on the outside, 

 inside with 2 rows of rounded teeth, separated by a groove which 



