THE WEST iJVlERICAN MOLLUSKS OF THE GENUS 

 TRIPHORIS. 



By Paul Bartsch, 



Assistant Curator, Division of Molluslcs, U. S. National Museum. 



The West American members of this wemis were first brought to 

 the attention of conchologists by Prof. C. B. Adams, who in 1852 

 described three species in his catalogue of shells collected at Panama/' 

 Triplioris alternatus, inconspicuus, and infrequens. Of these, the last, 

 Tri'plions infrequens has proved to be a Cerithiopsis^ Later,*" 

 Doctor Carpenter reported the occurrence of Triforis adversa Mon- 

 tagu, a common European species, on the West Coast. The speci- 

 mens referred to, by him, are not the Old World species but must be 

 cited under one or several of the forms described in the present 

 report. 



Through the kindness of Prof. John Tyler, of Amherst College, I 

 have been enabled to examine, redescribe, and figure, the original 

 specimen described byDoctor Adams. 



TRIPHORIS MONTEREYENSIS, new species. 

 Plate XVI, fig. 17. 



Shell rather stout, brown, with a wax-yellow band about one- 

 third the width of the height ot the whorls encirchng the middle of the 

 turns. (Nucleus decollated in all the specimens examined), post- 

 nuclear whorls separated by strongly channeled sutures, ornamented 

 on the early turns by a double spiraH row of tubercles and on the last 



«Ann. Lye. Nat. Hist., V, pp. 382-383. 

 b Proc. Zool. Soc. London, 1863, p. 350. 

 cRept. Brit. Ass. Adv. Sci., 1864, p. 613. 



<^ In the preparation of the present diagnosis the following terminology is used: 

 Spiral sculpture, the markings following the directions of the coils of the whorls. 

 Axial scidpture, the markings which extend from the summit of the whorls toward 

 the umbilicus. 



The axial sculi)ture may be — 



Vertical, when the markings are in general parallelism with the axis of the shell; 

 Protractive, when the markings slant from the preceding suture forward; 

 Retractive, when the markings slant from the suture backward. 



Proceedings U. S. National Museum, Vol. XXXIII— No. 1569. 



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