1920.] NATURAL SCIENCES OF PHILADELPHIA. 311 



15. A callous projection within the outer lip in adult .shells, none 

 in the throat; peripheral region convex; 5 well developed 



plaits M. hrunnea Pse. 



No lip callus; a nodule in the throat; carob brown to chestnut 

 brown, the aperture chocolate; last whorl somewhat cylin- 

 dric, smooth with spirals at the base; 4 plaits. 25 x 10.4, 

 aperture 14 mm. M. ticaonica vagans n. subsp. 



II. Shell conspicuously spirally lirate, axial sculpture subordinate or 



wanting; outer lip blunt or thin, crenulate, throat smooth. 



1. Diameter nearly half the length; with smooth spiral' cords, 



very little interstitial sculpture 2 



Shell more slender, with distinct interstitial sculpture 4 



2. Shell irregularly plicate axially; very pale with a thin brown 



epidermis M. turgida Rve. 



Shell not plicate : 3 



3. Orange, often with white peripheral maculation. 



ilf . tabanula Lam. 



Thin, fulvous M. suhrostrata Sowb. 



Brown with some white maculation M. proscissa Rve. 



White, variegated with smoky brown M. pudica Pse. 



4. Interliral spaces with an intermediate thread and close axial 



sculpture leaving narrow pits M. interlirata Rve. 



Having close low riblets, making the cords tubercular; 11 

 cords on last whorl; yellowish with 2 indistinct brown 

 bands, tubercles white; 3 columellar plaits. 11.6x4,5, ap- 

 erture 6.3 mm. M. waikikiensis n. sp. 



Having spaced axial impressed lines throughout; apex pink; 

 4 or 5 plaits. 



5. Spirals narrow, brown on a white ground; smaller than M. 



granaUna Lam., the brown lines continuous; 35.3x11.4, 



aperture 18 mm.; 8 post-embryonic whorls; Honolulu 



M. langfordi n. sp. 

 Spirals blunt, alternately larger and smaller; buff with a 

 broad chestnut peripheral band, its upper half interrupted 

 into a series of large spots; 29.3x9.3, aperture 16.4 mm.; 

 7^ post-embryonic whorls; near crenifera Lam., but smaller 

 with many more impressed axial lines M. emersoni n. sp. 



III. Vexillum. Axial ribs predominating over spiral sculpture 



when the latter is present. (In baldwini the later whorls 

 are smooth.) 



1. Shell obesely fusiform, with narrow aperture; outer lip con- 



spicuously receding or excised below, lirate within, a plait 



at its upper third; 5 or 6 plaits (Section Tdiochila, new) 2 



Outer lip normal, not receding below 3 



2. Last 3 or 4 whorls very smooth and glossy, marbled or streaked ; 



early whorls costulate V. baldwini Melv.6 



^V. baldwini has been collected at Honolulu by Ostergaard and Bryan. It 

 may prove to be identical with V. flanunulata Pse., of which I have not seen 

 specimens. V. baldwini and V. turbeM form a peculiar section to be called 

 Idiochila, the type being V. turben Reeve. 



