xo. 2166. WEST A MERICAN ALEC TRI ON I DAE— BALL. 577 



Alectrion Umacina Dall, new species. Shell very email, gUstening, yellowisli 

 white with flecks of brown, especially one on the anterior angle of the 

 outer lip; nuclear whorls smooth, three, followed by three and a half sculptured 

 whorls; axial sculpture of 8 or 10 ribs coronated at the suture and the shoulder, 

 crossed by two sharp narrow sulci between the sutures and by about six on the 

 last whorl with three stronger on the base; the ribs are obsolete anteriorly on the 

 last whorl; outer lip white, strongly varicose, with six or seven internal lirae. 

 Length, 5.3; diameter, 3 mm. Gulf of California in shallow water. (Cat No 

 274095, U.S.N.M.) 



Alectrion onchodes Dall, new species. A small, short, acute, swollen, evenly 

 reticulate, whitish shell with a channeled suture, three smooth nuclear and 

 three reticulate whorls, a heavily thickened outer lip with seven or eight 

 denticles inside; a smooth labium, subsutural nodule, and short canal. Length, 

 6 mm.; width, 5; spire, 2.5 mm. (Cat. No. 96827, U.S.N.M.) Collected from 

 off Cerros Island, Lower California, to Panama. 



Alectrion poHstes Dall, new species. Shell rather large, acute, with nine 

 rounded whorls of which about three are nuclear and smooth, the rest reticu- 

 late; the axial sculpture stronger, of (on the last whorl about 23) arcuate, similar, 

 narrow ribs with wider interspaces, crossed between the sutures by six or seven 

 flattish spirals with narrower channeled interspaces in which as a rule there are 

 no intercalary threads. The siphonal fasciole is in front of a deep sulcus, the 

 labial callus is thin and obscurely lirate; the outer lip varicose and internally 

 Urate, the canal very short. The color is yellowish white. Length, 24; width 

 15; length of aperture, 12 mm. (Cat. No. 96642, U.S.N.M.) This species has 

 been dredged from Pana ma Bay to Sechura Bay, Peru, in moderate depths of 

 water. 



Arcularia luteostoma Broderip and Sowerby, 1829. A. xanthostoma Gray, 1839, 

 IS synonymous. This very distinct species ranges from the Gulf of California 

 to Chile. 



Arcularia tiarula Kiener, 1834. Cape St. Lucas to Panama. This is the whitish, 

 polished, smooth-backed form with coronated last whorl and brown spots in front 

 of the suture, which with the two following forms has generally been regarded, 

 following Cxi-penter, as a variety of tegula. It is certain they are intimately 

 allied but are geographically of different distribution. This is the southern 

 form ranging from Cape St. Lucas to Panama. 



Arcularia nodulifera Philippi in Carpenter, 1857. This form is strongly spirally 

 sulcate and ranges from San Diego, California, to the Gulf of California. It is 

 usually dark gray with a rude surface. 



Arcularia tegula Reeve, 1853. This is the large, dark-colored form which ranges 

 from San Francisco to San Diego, California. 



Arcularia crebristriata Cari>enter, 1857 . This form ranges from Mazatlan to Salina 

 Cruz, Mexico. 



Arcularia complanata Powys, 1835. This is the dark form of which the two fol- 

 lowing may be geographical races. It ranges from Panama to Valparaiso. 



Arcularia major Steams, 1894. Larger, yellow brown, apparently quite distinct 

 from the preceding. Ranges from Panama to the Gulf of California. 



Arcularia iodes Dall, new species? Pale violet with darker violet spiral bands and 

 conspicuous white callus about the mouth. Smaller than vmjor or complanata 

 (Cat. No. 53946, U.S.N.M.) Gulf of California. 



Arcularia scabriuscula Powys, 1835. Nassa stimpsoniana C. B. Adams, 1852, is 

 synonymous. Ranges from Montijo Bay, Central America, to Panama. ' 

 36399°— Proc.N.M.vol.51— 16 37 



