MOLLUSCA FKOM KKUIT IILNDKIOD FATHOMS — IlKDMCV. •{59 



Arculauia dipsacoides, sp. nov. 

 (Plate Ixvii., fig. 21). 



Shell ovate, rather thin, remarkably tabulate. \Viiorl>i eight 

 of which half are comprised in the protoconch. Colour, cream, 

 except the protoconch which is pale purple. Sculpture, protoconch 

 conical, smooth, with a peripheral keel which is just exposed above 

 the suture of the succeeding whorls. In the adult whorls spiral 

 threads reticulate radial riblets, producing sharp tuberculate 

 granules at the point of intersection, on the last whorl there 

 are eleven spirals and twenty-two radials, both cease on the base 

 and vanish on the subsutural shelf, the radials mount the spire 

 obliquely, between the riblets are fine radial threads. Behind the 

 canal a broad furrow encircles the base. The aperture is without 

 the thickening usual in the genus, which gives an unfinished 

 aspect to the shell, outer lip sharp and denticulate by the external 

 sculpture. Three rest stages on the last whorl are indicated by 

 thin lamelhe followed by grooves. A thick callus layer is spread 

 over the inner lip. Canal very short, recurved, the truncate base 

 of the columella bent outwards. Length, 12, breadth 8 mm. 



This species appears to be abundant and wide spread in deep 

 water. Besides the present station in 800 fathoms, it was taken 

 in plenty by Mr. W. F. Petterd and myself in 250 and 300 

 fathoms. It was misquoted in our report (ante p. 214) as Nassa 

 jaeksoiiemis, Q. & G.. Dr. J. C. Verco has shown me examples 

 of A. dipsacoides wliich lie drerlged in deep water oft' the coast of 

 S. Australia. 



Of published species the nearest ally is iVdssa rpluomtlla, 

 Watson,'' from deep water oft' New Zealand. The novelty is of 

 smaller size, with smaller and more numerous granules. 



The familiar Kassa of Lamarck^ is not here employed because 

 Dr. W. H. Dair has pointed out that Nansa was earlier used by 

 Bolten'' with a difterent meaning, namely for the group of 

 Buccinnm i^prhim., Bruguiere, generallj' known by Adams' name 

 of lopan. 



« Watson— Clmh. Rep., Zool., xv., 188() p. 187, \A. xi., f. J). 



7 Lamarck— Mem. Soc. Hist. Nat. Paris, 1799, p. 71. 



" Dall -Joiirn. of Conch., xi., 1906, p. 295. 



'J Bolten -Mus. Bolten., (2), 1798, p. 132. 



