37 
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. 
Puevroroma nositis. Pleur. testd fusiformi, solidd, rugosa ; an- 
fractibus superné concavis, leviter striatis, prope mediam carind 
mazximd, inferne, precipue ultimo, carinis parvis alternantibus ; su- 
turd simplici ; labio externo subintegro, interno inferne paululim 
producto ; epidermide pallid? fuscd indutd. Axis 44 lin. 
Hab. San Blas, Mexico. From seven fathoms; mud. 
This is a very considerably larger shell than P. ovytropis, 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. 
Pievroroma cemMaTa. Pleur. testd fusiformi, elongatd, gracilli- 
md, fuscd ; anfractibus numerosis, medio uniseriatim tuberculato- 
carinatis ; tuberculis rectis, subquadratis, albidis ; carinis duabus, 
parvis, suturam comitantibus, anfractu ultimo multicarinatis ; 
sinu laterali pon® carinam ; apertura ovali ; cunali elongatd. Axis 
9 lin. 
Hab. Gulf of Magdalena, California. Obtained from seven fathoms, 
among sandy mud. 
Puevrotoma supata. Pleur. testd fusiformi, acuminatd, levigatd, 
fulvd ; anfractibus medio carinatis, superné granulis uniseriatim 
cinctis, infern® carind parva unica, sed ultimo pluribus ; suturd 
carinatd ; canali breviusculo. Axis 12 lin. 
Hab. The China Sea and north coast of Sumatra: dredged from a 
muddy bottom in eighteen fathoms. 
Prevrotoma strouipa. Pleur. testdé fusiformi, levigatd, corned ; 
anfractibus superne planulatis, inferneé costatis ; costulis albidis, 
brevibus, obliquis, in anfractu ultimo evanidis ; apice papillari ; 
suturd simplici ; canali brevi ; labio externo tenui. Axis 14 lin. 
Hab. Lagulhas Bank, Cape of Good Hope: dredged from a depth 
of forty-three fathoms. 
Prevroroma Gravis. Pleur. testa fusiformi, levigatd, corned ; an- 
fractibus prope suturam angulatis, uniseriatim tuberculis parvis 
albidis cinctis, superné late planulatis ; anfractu ultimo coarctato ; 
apice papillari; suturd simplici, fere occultd, canali brevi ; aper- 
turd fuscd. Axis 11 lin. 
Hab. Lagulhas Bank, Cape of Good Hope; in company with the 
preceding. 
PLevurotTomaA INERMIS. Pleur. testa ovatd, acuminatd, inermi ; an- 
fractibus subrotundatis, flammeis undosis fuscis longitudinaliter 
ornatis, transversim striatis; suturd simplict; aperturd ovali ; 
canali brevi. Axis 15 lin. 
ei Bay of Magdalena, California. From seven fathoms ; sandy 
mud. 
