33 
Hab. Panama, St. Blas, Gulf of Nicoya, &c. 
This shell is of a straight solid growth, and cannot well be con- 
founded with any species hitherto described. 
Prevrotoma Papauis. Pleur. testé fusiformi, acuté turritd, pal- 
lid? luteo-brunnescente, anfractibus superne concavis, longitudina- 
liter leviter liratis, liris numerosis, anfractu ultimo pallide albo- 
fasciato ; canali brevi. Long. 12; lat. 3 poll. 
Pleurotoma mitreformis var., Kiener. 
Hab. ? 
After carefully examining one or two specimens of this shell, which 
Kiener describes as a variety of the Pleurotoma mitreformis, Iam 
forced to the conclusion that it is specifically distinct. 
Pievrotoma opesa. Pleur. testd obeso-fusiformi; spird turritd, 
anfractibus luteolis, superne albis, lineis fulvis, obliquis, longitu- 
dinaliter venosis ; labro acuto, sinu subcentrali; canali mediocri, 
brevi subitd refleco. Long. 13; Jat. 3 poll. 
Hab. ? 
The solid obesity of this shell has suggested the above title. 
Pievrotroma vircinea (Beck, MSS.). Pleur. testd fusiformi- 
turritd, pallidé luteold ; anfractibus in medio angulatis, tuberculis 
minutis albis seriatim cinctis ; anfractu ultimo multiseriatim gra- 
nuloso ; canali mediocri, leviter recurvo. Long. 13; lat. 3 poll. 
Hab. Mouth of the Gambia. 
This shell, though comparatively common in our collections, does 
not appear to have been hitherto described. 
PLevRoToMA annutaTa. Fleur. testd solidd, subulatd, brunned ; 
anfractibus leviter convewis, liris levibus, pallidioribus, numerosis, 
annulatim cinctis ; canali subelongato. Long. 14; lat. 2 poll. 
This shell is not very much unlike the Pleurotoma Deshayesit; it 
may however be readily distinguished from that species by the num- 
ber of well-marked ring-like ridges by which the entire surface is 
encircled. 
Pievrotoma caTENA. Pleur. testd elongato-fusiformi, turritd, acu- 
minatd, flavido-grised ; anfractibus medio valde convewis, quasi 
subitd tumidis, tuberculis eximiis, albis, obliquis, seriatim coro- 
natis ; labro tenui, sinu lato; canali elongato, recto. Long. 2}; 
lat. 5 poll. 
Hab. ? 
The leading feature of this new and very distinct shell is the bright 
perlaceous series of link-shaped tubercles which run round the peri- 
phery of the whorls. 
Genus Pecruncutvs. 
Pecruncutus Gicanteus. Peet. testd valde convead (juniore de- 
pressd), solidd, giganted, longitudinaliter striatd, striis contiguis, 
regularibus, et sulcata sulcis fere obsoletis ; albd, infern? castaneo- 
