Ancilla.] GASTROPODA. 451 



by callous growth, whereas the upper portion of the columella is thick, 

 callous, or gibbose. A depression or groove usually separates the 

 callosity of the spire from what is commonly called the '' smooth 

 zone," though this zone is often not as smooth as the callous spire, 

 especially when strongly exhibiting the lines of growth ; the relative 

 size of this zone is of specific value taken in conjunction with cognate 

 characters. Aperture grooved above, and truncate and deeply sinuous 

 below. Operculum horny, elongate-oval, obtuse at both ends, the 

 nucleus subapical. 



Distribution. About fifty species are known, inhabiting tropical 

 and warm seas Ked Sea, Indian Ocean, Japan, Australasia, Polynesia, 

 Africa, &c. 



The earliest fossils are from the Cretaceous and Eocene. 



KEY TO SPECIES. 



. Spire with a very thick callosity, its height about two-thirds 

 that of the aperture ; apex blunt ; body-whorl bluish to 

 dark brown, banded with white and brown ; 19 mm. by 

 34 mm. to 22 mm. by 44 mm. . . . . . . australis. 



b. Similar to A. australis, but the callosity on the spire moderate, 



apex sharply pointed . . . . . . . . pyramidalis. 



c. Shell small, narrowly ovate, spire with a thin callus, about half 



the height of the aperture ; body-whorl fawn, banded with 



white and brown ; 4J mm. by 9^ mm. . . . . . . bicolor. 



d. Similar to A. pyramidalis, but the body- whorl broadened above 



and nattish on the ventral side ; 8| mm. by 15 mm. to 



23 mm. by 42 mm. . . . . . . . . . . depressa. 



e. Shell elongated oblong ; spire very callous, its height more 



than half that of the aperture ; apex mucronate ; body- 

 whorl fawn colour, banded with white and light brown ; 

 11 mm. by 22 mm. to 21 mm. by 45 mm. . . . . mucronata. 



1. Ancilla australis, Sowerby, 1830. Plate, 49, fig. 1. 



Ancillaria australis, Sow., Spec. Conch vl., 1830, 7, f. 4446 ; Voy. Astrol., 

 iii, 20, pi. 49, f. 13-17 ; Thes. Conch., iii, 63, pi. 211, f. 1, 2 ; Conch. 

 Icon., xv, pi. 3, f. 7 ; M.N.Z.M., 58 ; T.N.Z.L, xvi, 223 ; Harris, C. 

 Tert. M.B.M., i, 76 ; Man. Conch. (1), v, 94, pi. 38, f. 28. A. rubiginosa, 

 Swains. : Suter, T.N.Z.I., xxxviii, 332 ; not of Swainson. 



Shell elongately oval, with a short spire, covered by a thick callosity ; 

 leaden-blue and brown. Sculpture consisting of fine vertical growth- 

 lines, crossed by very fine dense spiral striae, sometimes distinct axial 

 plications appear on the last whorl on approaching the aperture ; base 

 with an oblique narrow light depression above the slightly raised 

 fascicle, which is somewhat excavated in the middle and more or less 

 angularly plicated. Colour : Spire yellow or reddish-brown, followed 

 by a broad chestnut spiral band, margined with white below ; the 

 centre of the body- whorl is bluish to dark brown, vertically lined 

 with white or bluish ; the basal narrow groove is bluish-brown, mar- 

 gined above and below with white ; the fascicle consists of three 

 parts, the upper lightly elevated and the median depressed parts are 



15* 



