494 GASTROPODA. [Pectinibranchia. 



fine rather irregular incremental lines, which, however, become more 

 prominent en the lower whorls, connecting the small tubercles below 

 the suture with the larger ones on the keel. Colour light cream. Spire 

 conical, about as high as the aperture. Protoconch consisting of 1| to 

 2 whorls, the nucleus obtuse, smooth, polished, the succeeding volution 

 with minute spiral striae. Whorls 7, slowly and regularly increasing, 

 with a strong carina below the middle, excavated above and straight 

 below the keel ; base convex, ending in a slightly twisted rather short 

 beak. Suture deep and margined below with a row of small elongate 

 gemmules. Aperture pyriform, rather narrow, angular above, termi- 

 nating in a short open and truncated canal, which has a slight turn 

 to the right. Outer lip sharp, strongly angled, and with a well- 

 pronounced rounded sinus at the keel, contracted towards the base. 

 Columella nearly straight, with an oblique thickening, slightly sinuated 

 and pointed below. Inner lip forming a very thin obliquely finely 

 striated layer on the columella and body. 



Diameter, 8-5 mm. ; height, 19-6 mm. Angle of spire, 42. 



Animal unknown. 



Type of P. tuberculata in the Dominion Museum, Wellington. 



Hob. Off Great Barrier Island, in 110 fathoms ; near Cuvier 

 Island, in 37 fathoms (Captain Bollons). 



Remarks. Of this species a smaller form occurs, but similarly 

 sculptured, and it seems scarcely worth a varietal name. It is also 

 found in the Wanganui blue clay of Pliocene age. The larger type 

 specimens in the Dominion Museum are from the Petane Pliocene ; 

 in these, as also in the smaller form, the tubercles are less strong and 

 more numerous than in Recent examples. This species is a typical 

 Bathytoma. 



Fossil in the Pliocene. 



Subfam. 4. MANGILIIN.E. 

 No operculum. Labial sinus at the suture. Protoconch papillate. 



KEY TO GENERA. 



A. Lip thick, varicose, smooth inside ; sinus moderately deep : 



protoconch papillate . . . . . MANGILIA. 



B. Lip thin, dilated towards the base ; sinus deep ; canal short, 



not notched at the base ; whorls finely cancellated ; proto- 

 conch polygyrate, reticulated . . . . . . . . DAPHNELLA. 



Genus 1. MANGILIA (emend.), Risso, 1826. 



Mangelia, Risso, Hist. Nat. Europe Merid., iv, 1826, 219. Type : 

 M. costidata, Risso. Clathromangelia, Monts., 1884. Cytharella, Monts., 

 1875. Pseudoraphitoma, Boettg., 1895. Paraclctthurelia, Boettg., 1895 

 (fide Cossmann). 



Animal with slender tentacles, and bearing the eyes at various 

 heights on external bulgings. Foot ample, truncate in front. Siphon 

 produced beyond the canal ; 2 branchial plumes. Teeth of radula 

 having the formula 1 + 0+1 ; the teeth triangular. 



