512 GASTROPODA. [Pectinibranchia. 



spiral sculpture, thin and sharp. Columella vertical, straight, lightly 

 excavated toward the flat parietal wall. Inner Up very thin and narrow, 

 smooth. 



Diameter, 1-1 mm. ; height, 2-8 mm., with 5 whorls. 



Animal unknown. 



Type in my collection. 



Hob. Foveaux Strait, in 15 fathoms, type (A. Hamilton) ; Wha- 

 ngaroa Harbour (C. Traill) ; near the Snares, in 50 fathoms (Captain 

 Bollons) ; Chatham Islands. 



Remarks. This species, no doubt, is in form and sculpture very 

 much like D. lacunosa, Hutt., but the fossil form is nearly twice as 

 high (5 mm.), and there is no evidence that the protoconch is striate. 

 I therefore consider it advisable to make the Recent form the type 

 of a new species. It is much smaller than the also nearly allied 

 D. chariessa, Sut., which has more spirals on a whorl, and a much 

 higher and smooth protoconch. 



Subgen. 1. THESBIA, Jeffreys, 1867. 

 Type : T. nana, Loven. 



Shell small, bucciniform ; spire short, subconoidal ; protoconch 

 paucispiral, globose, nucleus papillate ; whorls convex, smooth, the 

 last relatively very large, the base gradually narrowed ; aperture 

 ovate, contracted below, terminating in a short truncated and straight 

 canal ; sinus on the outer lip very small ; columella slightly sinuous ; 

 inner lip thin, narrow. 



KEY TO SPECIES. 



A. Whorls convex . . . . . . . . . . membranacea. 



B. Whorls angulated . . . . . . . . . . xanthias. 



11. Daphnella membranacea, Watson, 1886. Plate 22, fig. 18. 



Pleurotoma (Thesbia) membranacea, Wats., Chall. Rep., xv, 333, pi. 26, f. 9. 

 Daphnella membranacea, Suter, T.N.Z.I., xxxi, 77 ; Index, 71. 



Shell broad and short, tumid, membranaceously thin, feebly spiralled, 

 white, base long and gradually contracted. Sculpture consisting of 

 very slight impressed lines and flat feeble spiral threadlets, which are 

 irregular and interrupted at every biggish line of growth, feebler, 

 broader, and more regular just below the suture. Colour white, under 

 a brownish-yellow smooth glossy thin epidermis, entirely trans- 

 lucent. Spire short-pointed, conical, not much higher than half the 

 height of the aperture. Protoconch eroded, evidently small. Whorls 5 

 remaining ; they are short, broadish, a little tumid, convex ; the last 

 is large, tumid, and elongated, drawn out at the base. Suture dis- 

 tinct, linear, and slight. Aperture sernilunar, sharply angulated above 

 and below, the canal broad but somewhat broken. Outer lip very 

 thin, regularly curved, with a deep wide sinus close up to the suture, 

 whence the front edge of the shell makes a prodigious forward and 



