298 BULLETIN : MUSEUM OF COMPAEATIVE ZOOLOGY. 



It may be well to recall here that the shell to which I originally gave the name 



of Volutilithes philippiana, which is an evident descendant of some of the Chilian 

 and Patagonian Tertiary types, is now known to possess a membranous proto- 

 conch, and was referred by me, together with its fossil allies, to a section of Adelo- 

 melon under the name of Miomelon (Feb., 1907). Kot aware of this fact, my 

 friend, Dr. von Ihering of San Paulo, Brazil, in June of the same year, proposed 

 for the same group of species the genus Proscaphella, with P. gracilior Ihering, 

 as type. This is the Valuta gracilis of Philippi, not of Lamarck. While the 

 sculpture of these species is rather characteristic, they are united with the Ter- 

 tiary ancestors of the recent Adelomelon by somewhat intermediate gradations, 

 and tlierefore I think that they can hardly be more than subgenerically separated 

 from each other.^ 



Excepting A. stearnsii of Alaska, which perhaps reached American waters by 

 ancestral emigration along the western shores of the Pacific, the most northerly 

 species of Adelomelon is the following shell. 



Adelomelon benthalis Dall. 



Plate 5, figure 8. 



Scaphella benthalis Dall, Proc. U. S. Nat. Mus., 1896, 18, p. 13. 



Adelomelon benthalis Dall, Smithsonian Misc. Coll. Quarterly, Feb., 1907, 48, p. 357. 



Shell recalling A. magellanica, Sowerby, but stouter, with more rounded 

 whorls, the aperture shorter and wider, with a broad flexure where the lip turns 

 to meet the body whorl, while in A. magellanica the posterior part of the aperture 

 is pointed ; the latter has two strong plaits on the pillar ; A. benthalis has three, 

 all obsolete, the middle one most perceptible, and has a less marked canal and 

 siphonal fascicle. The interior of the aperture is pale flesh color ; the exterior 

 seems to have been like that of A. magellanica, but is almost entirely decorti- 

 cated. It has five whorls beside the nucleus, and there is no operculum. Height, 

 125 ; of the last whorl, 90 ; of the aperture, 70 ; width of the aperture, 35 ; of 

 the (decorticated) shell, 60 mm. 



U. S. S. "Albatross," station 3360, in 1672 fathoms, sand, in the Gulf of 

 Panama, temperature at bottom 42o F. U. S. N. Mus. 122,998. 



At first siglit one would be disposed to think that tliis specimen represented a 

 nortliward extension by 3360 miles of one of the Magellanic species, but a more 

 careful examination shows numerous points of difference. 



The whorls are more nearly tabulate in front of the suture, the whorls rounder, 

 the spire more rapidly tapering and relatively longer. 



* By the misplacement of some paragraphs in the paper above cited, the genus 

 Zidona lins hten inserted in tiie text before, instead of after, the portion treating 

 of Miomelon, o/>. cit., p. 303-S66. 



