312 BULLETIN: MUSEUM OE COMPARATIVE ZOOLOGY. 



ble; -n-horls moderately rounded, suture appressed; axial sculpture of, on tbe 

 last vrliorl, about ten, inconspicuous vertical ribs, wbich bear, near the suture, 

 a feeble spiral row, at the shoulder a very conspicuous row, and on the body 

 of the last whorl three less conspicuous rows, of smooth, more or less orange- 

 tinted, rounded, prominent nodules; between the spiral rows of nodules there are 

 four or five equal and equidistant fine spiral stnae ; the surface of the shell is 

 subtranslucent, recalling that of Purpura lapillus L. ; aperture ovate, in the adult 

 minutely channelled behind, glazed with a rich orange enamel, contracted sharply 

 at the beginning of the canal; outer lip not reflected, thin-edged, with an internal 

 thickening which is faintly lirate ; body with a broad layer of callus, of which the 

 left hand or outer border is a little raised ; a small subsutural nodule in the adult 

 and one on each side the entrance to the canal ; pillar short, canal very short, 

 deep, and strongly recurved, making a very prominent siphonal fasciole with 

 a constriction behind it, and deep umbilical chink between it and the reflected 

 edge of the columellar callus. Lon. of shell, 15.5 ; of last whorl, 10.0; of aper- 

 ture and canal, 7-0 ; max. diam. 6.5 mm. 



Collected by the " Albatross" party on the reefs at Easter Island. U. S. N. 

 Mus. 110,767. 



This shell is not an Aspella, as it wants the peculiar clialky surface of that 

 genus and has a totally diff'erent sculpture; but I am unable to suggest any 

 group which seems more similar. 



The radula is most like that of Trophon dathra'us as figured by Troschel, 

 Gebiss der Schnecken, 2, pi. 11, figure 17, but differs in having the outer cusps 

 of the rhachidiau tooth nearer the outer ends of the basal plate, straighter, and the 

 central cusp of the same tooth longer and more prominent. The laterals have 

 also longer and stronger cusps, though of the same general shape. 



The upper surface of the mouth is covered by a thin, smooth layer of chitinc, 

 while the anterior margin of the layer is modified into an evenly arched thick- 

 ened narrow ridge performing the office of a jaw, with the middle part sculptured 

 with many minute spicules or projecting needle-like spines. 



The operculum is more or less lozenge-shaped, purpuroid, with a marginal 

 coating of reddish brown enamel on the inner face. 



The tentacles were slender and small and the eyes present, though details 

 could hardly be had since the data were obtained from a soakcd-out specimen 

 which had been dried in the shell. 



The shell is not a Trophon or Boreotrophon in the strict sense ; iu coucholog- 

 ical and opercular characters it differs from Aspella ; it cannot be referred to 

 Purpura (= Thais) or !Murex, and I am therefore constrained to propose a new 

 sectional name for it with the following chanicters : 



Shell small, with nodular sculjjture ; the aperture with a projecting margin, 

 feebly lirate within the outer lip when adult, constricted in front at the beginning 

 of the canal; dentition like Boreotrophon; operculum purpuroid, lozcnge-sliapcd, 

 with a raised border on the inside face ; month provided with an arcuate chitinous 

 jaw. 



