NO. 2002. DIAGNOSES OF NEW PACIFIC SHELLS— DALL. 591 



last whorl with four strong, beaded, spiral cords with subequal inter- 

 spaces, peripherally; between them and the suture, three shghtly 

 smaller similar cords, the space at the suture giving a channeled effect; 

 on the base two less prominent cords and two wider nodulous ridges 

 around the deep, rather narrow umbiHcus; aperture circular, the 

 outer hp thick, fringed by the ends of the spiral cords; axial sculpture 

 of numerous fine radial threads, most obvious in the channels between 

 the cords; height of shell, 4.5; maximum diameter of base, 5.5 mm. 



Beach, San Josef Island, Gulf of Cahfornia, Cat. No. 264972, 

 U.S.N.M. 



Operculum multispiral, calcareous externally with a small central pit. 



BOLMA BARTSCHII, new species. 



Shell thin, trochoid, yellowish white with rose-colored flammules 

 and nebulosities, with more or less articulation on the spiral ridges. 

 Nucleus very minute, glassy; nepionic shell white, depressed above, of 

 three rather rounded whorls with numerous low radial pHcations or 

 riblets; subsequent whorls four, with a sparsely imbricate keel at the 

 periphery and a prominent, beaded, spiral cord one-third of the way 

 from the appressed posterior suture toward the periphery. This 

 arrangement gives a channeled or turriculate aspect to the shell in 

 the sutural region. The last whorl has a third keel, imbricate hke 

 the peripheral one but less prominent, bordering the base; the space 

 between the beaded cord and the peripheral keel is on the upper 

 whorls finely spirally striated, but on the last whorl, first two, and 

 then a third, small spiral equidistant threads, articulated white and 

 dark rose color, are developed; the imbrications on the two keels are 

 short, distant, subspinose, and channeled in front; the base is nearly 

 smooth, with fine spiral striation and a widespread, transparent, thin 

 layer of enamel in front of the aperture; pillar smooth, arcuate, pearly; 

 outer hp thin, sharp, markedly expanded; throat pearly; aperture 

 quite obhque; operculum white, smooth, constructed hke that of 

 B. rugosa, but with the external depression much less marked; altitude 

 of shell 30, maximum diameter 35, diameter of operculum 15 mm. 



Dredged in 205 fathoms, sand, off Dowarra Island, near Ternate, 

 Moluccas. Cat. No. 214444, U.S.N.M. 



The shell was so tightly closed by the operculum that the animal 

 had decayed, though put in spirits, but the radula was preserved and 

 showed a central tooth of squarish form without cusps, on a larger 

 base, with four laterals on each side; their cusps denticulate with a 

 prominent spur below, behind the cusp, and the usual large mass of 

 uncini. From what was left of it, the sides of the foot seemed desti- 

 tute of any epipodial appendages. 



This very lovely shell is so thin and dehcate that it was a surprise 

 to find it possessing a heavy calcareous operculum. 



It is named after Dr. Paul Bartsch. 



