ON THE MOLLUSCA OF THE " CHALLENGER EXPEDITION. 



413 



Mollusc a or H.M.S. ' Challenges ' Expedition. — Part IX. 

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



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



[Eead June 2, 1881.] 

 Earn. Pleueotomid^e {continued). 



Pleueotoma, Lam. 



18. Pleurotoma (Drillia) gypsata, 

 n. sp. 

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

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



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

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

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

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

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

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

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

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



29. P. (Crassispira) climacota, 



n. sp. 



30. P. ( Clavus) marmarina, n. sp. 



31. P. [Mangelia) subtilis, n. sp. 



32. P. (M.) levuhensis, n. sp. 



33. P. (M.) eritmeta, n. sp. 



34. P. (M.) hypsela, n. sp. 



35. Pleurotoma (Mangelia) acan- 



thodes, n. sp. 



36. P. (M.) corallina, n. sp. 



37. P. (M.) macra, n. sp. 



38. P. (M.) incincta, n. sp. 



39. P. (ilf.) ^'ar«, n. sp. 



40. P. (Rhapkitoma) lithocolleta, 



n. sp. 



41. P. (ii.J 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, n. sp. 



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



18. Pleueotoma (Deillia) gtpsata, n. sp. 



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

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

 rature 40°. 



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

 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, and 

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



LINN. JOURN. — ZOOLOGY, VOL. XV. 32 



