NO. 2134. NOTES ON CHRYSODOMUS—DALL. 215 



Section SULCOSIPHO Ball. 



Shell like Chrysodomus but more slender and elongate and with 

 the whorl in front of the suture conspicuously widely sulcate or tabu- 

 late, the nucleus inflated and slightly oblique, the color whitish. 



Type. — Chrysodomus tabulatus Baird, Puget Sound. C. adelphicus 

 Dall, of Japan, appears to belong to this group also. 



Subgenus Barbitonia Dall. 



Shell short and stout, resembling Chrysodomus^ smooth or 

 axially ribbed, the outer wall of the aperture in the adult spirally 

 lirate within. Habitat, Northeastern Asia and Japan. 



Type. — Fusus arthnticus Valenciennes, 1858, Hakodate. 



The closely related Neptunea cumingi Crosse, 1862, according to 

 Aurivillius, has a radula differing from that of typical Chrysodomus 

 in having two rather long cusps on the laterals, the rhachidian tooth 

 bearing two curved cusps springing backward from the anterior 

 edge of the basal plate, and between them on the posterior edge of 

 the plate two short triangular cusps with no median denticle. The 

 operculum is large, slightly arched with an apical nucleus. Fusus 

 hulhaceus Bernardi, and vinosus Dall, have the dentition of Chryso- 

 dorauSs lack axial ribbing and lirations, and, though otherwise simi- 

 lar, do not belong to this group. 



Genus SEARLESIA Harmer. 



Searlesia Harmek, Pliocene Moll, Gt. Britain, vol. 1, 1915, p. 135. Type, 



TropJwn costifer S. Wood, Crag of Britain. 

 Chrysodomus Cossmann, Essais, vol. 4, 1901, p. 101. 



Nucleus (of jS. dirus) smooth, of two laxly coiled smooth whorls 

 changing abruptly into the adult sculpture of few strong axial ribs 

 crossed by numerous spiral threads. The shell-structure subtrans- 

 lucent, dark colored; the shell short-fusiform, periostracum incon- 

 spicuous; aperture shorter than the spire, the outer lip thickened 

 and internally lirate ; the body callous, with a narrow chink between 

 the reflected enamel and the strong siphonal fasciole; canal short, 

 open, slightly recurved. Radular formula i : ^ : ^, the median rachi- 

 dian cusp longer than the others. 



The specimens of T. costifer at my disposal show the nucleus less 

 perfectly than the recent species from which I have taken the de- 

 scription, but they appear to be essentially similar. The genus is 

 convenient as it takes in several West American and Japanese species 

 for which no satisfactory place had hitherto been found. The 

 operculum is similar to that of Colus^ long-ovate, arcuate, with 

 apical nucleus and, on the proximal side, a marginal band of vitreous 

 enamel. 



