Zoological Society. 137 



rican and Asiatic Seas, but are remarkably absent from the Pacific 

 Ocean. They never occur on the shores, being always obtained 

 from deep water, and usually on a muddy bottom ; to this latter 

 circumstance is probably attributable their singular absence from the 

 Pacific, where coral prevails. 



Pleurotoma nobilis. Pleur. testd fusiformi, solidd, rugosd ; an- 

 fractibus superne concavis, leviter striatis, prope medium carina 

 maximd, inferne, prcecipue ultimo, carinis parvis alternantibus ; su- 

 turd simplici ; labia externa subintegro, interna inferne paululiim 

 producta ; epidermide pallide fused indutd. Axis 44 lin. 

 Hab. San Bias, Mexico. From seven fathoms ; mud. 

 This is a very considerably larger shell than P. axytropis, but in 

 the character of the sculpture they closely approach each other. It 

 is chiefly distinguishable from it in the absence of any keel between 

 the principal keel and the suture, and in some minor characters. 

 Pleurotoma gemmata. Pleur. testd fusifarmi, elongatd, gracilli- 

 md, fused; anfractibus numerosis, medio uniseriatim tuberculato- 

 carinatis ; tuberculis rectis, subquadratis, albidis ; carinis duabus, 

 parvis, suturam comitantibus, anfractu ultima multicarinatis ; 

 sinu laterali pane carinam ; aperturd ovali ; canali elongatd. Axis 

 9 lin. 

 Hab. Gulf of Magdalena, California. Obtained from seven fathoms, 

 among sandy mud. 



Pleurotoma jubata. Pleur. testd fusiformi, acuminatd, Icevigatd, 



fulvd ; anfractibus media carinatis, superne granulis uniseriatim 



cinctis, inferne carind parvd unicd, sed ultimo pluribus ; suturd 



carinatd ; canali breviuscula. Axis 12 lin. 



Hab. The China Sea and north coast of Sumatra : dredged from a 



muddy bottom in eighteen fathoms. 



Pleurotoma stolida. Pleur. testd fusiformi, l<£vigatd, corned; 

 anfractibus superne planulatis, inferne castatis ; castulis albidis, 

 brevibus, obliquis, in anfractu ultimo evanidis ; apice papillari ; 

 suturd simplici ; canali brevi ; labia externo tenui. Axis 14 lin. 



Hab. Lagulhas Bank, Cape of Good Hope : dredged from a depth 

 of forty-three fathoms. 



Pleurotoma gravis. Pleur. testd fusifarmi, Icevigatd, corned ; an- 

 fractibus prope suturam angulatis, uniseriatim tuberculis parvis 

 albidis cinctis, superne late planulatis ; anfractu ultimo caarctata ; 

 apice papillari ; suturd simplici, fere occultd, canali brevi ; aper- 

 turd fused. Axis 11 lin. 



Hab. Lagulhas Bank, Cape of Good Hope; in company with the 

 preceding. 



Pleurotoma inermis. Pleur. testd avatd, acuminatd, inermi; an- 

 fractibus subrotundatis, flammeis undasis fuscis longitudinaliter 

 ornatis, transversim striatis; suturd simplici; aperturd ovali; 

 canali brevi. Axis 15 lin. 

 Hah. Bay of Magdalena, California. From seven fathoms ; sandy 

 mud. 



