ON THE MOLLUSCA OF THE ' CHALLENGER ' EXPEDITION. 413 



Mollusca of H.M.S. 'Challenger' Expedition. — Part IX. 

 By the Rev. Robert Boog Watson, B.A., F.B.S.E., F.L.S., &c. 



[Published by permission of the Lords Commissioners of the Treasury.] 



[Bead June 2, 1881.] 

 Fam. Pleurotomid.e (continued). 



Pleurotoma, Lam. 



18. 



19, 

 20. 

 21. 

 22. 

 23. 

 24. 

 25. 

 26. 

 27- 

 28. 

 29. 



30. 

 31. 



32. 

 33. 

 34. 



Pleurotoma (Drillia) gypsaia, 



n. sp. 

 P. (D.) brachytona, n. sp. 

 P. (D.) fiuctuosa, n. sp, 

 P. (D.) bulbacea, n. sp. 

 P. (D.) spicea, n. sp. 

 P. (D.) w/a, n. sp. 

 P. (D.) stirophora, n. sp. 

 P. (D. ) phceacra, n. sp. 

 P. (D.) tmeta, n. sp. 

 P. (JD.) incilis, n. sp. 

 P. (D.) sterrha, n. sp. 

 P. (Crassispira) climacota, 



n. sp. 

 P. ( Clavus) marmarina, n. sp. 

 P. (Mangelia) subtilis, n. sp. 

 P. (3/.) levukensis, n. sp. 

 P. (3f.) eritmeta, n. sp. 

 P. (3/.) hypsela, n. sp. 



35. Pleurotoma (Mangelia) acan- 



thodes, n. sp. 



36. P. (3f.) corallina, n. sp. 



37. P. (3/.) macra, n. sp. 



38. P. (3f.) incincta, n. sp. 



39. P. (M ) ^«ra, n. sp. 



40. P. (Rhaphitoma) lithocolleta, 



n. sp. 



41. P. (R.) lincta, n. sp. 



42. P. (Thesbia) eritima, n. sp. 



43. P. (T.) translucida, n. sp. 



44. P. (T.) corpulenta, n. sp. 



45. P. (T.) platamodes, n. sp. 



46. P. (T.) dyscrita, n. sp. 



47. P. (T.) monoceros, n. sp. 



48. P. (T.) papyracea, n. sp. 



49. P. (T.) brychia,\\. sp. 



50. P. (T.) pruina, n. sp. 



IS. Pleurotoma (Drillia) gypsata, n. sp. 



St. 169. July 10, 1874. Lat. 37° 34' S., long. 179° 22' E. 

 N.E. from New Zealand. 700 fins. Grey ooze. Bottom tempe- 

 rature 40°. 



Shell. — Strong, fusiform, biconical, scalar, shortly, sharply aud 

 obliquely ribbed, keeled, constricted at the suture, with a long 

 and rather inflated body-whorl and a largish snout. Sculpture. 

 Longitudinals — on each whorl is a strongish angulation, forming 

 a shoulder, crowned by a series of narrow elongated tubercles or 

 short ribs ; this coronated keel lies on the earlier whorls below, 

 but on the later above the middle. The ribs do not reach the lower 

 suture ; in shape and breadth they are irregular, but are always 

 somewhat swollen in the middle and pinched up into prominence ; 

 they are parted by flat open furrows of nearly double their width : 

 on the body-whorl they extend very little below the shoulder, aud 

 still less above it. There are about twenty of these ribs on the 



LINN. JOURN. — ZOOLOGY, YOL. XV. 32 



