Fossils from the Miura Peninsula and its Immediate North. (55 



nodulous longitudinal ribs, numerous, unequal spiral riblets or 

 threads, thickened outer lip, a tubercle-like process on the inner 

 lip near the posterior angle of the aperture and short recurved 

 canal. 



Fossil occurrence. — Kamakura Zone (Kewaizaka in Kama- 

 kura); Kanazawa Zone (Nojirna); Koshiba Zone (Koshiba). 

 Upper Musashino of Kazusa. 



Living. — Northern Japan; Alaska; Oregon; Chile; Strait of 

 Magellan. 



59. Triton subpyrivm, Yokoyama. 



Pl. IV. Figs. 3, 4. 



Shell subpyriform, swollen, thick, with spire low, much 

 shorter than the body-whorl. Whorls very weakly angulated in 

 the middle, the angle being sometimes indistinct. The surface 

 above the angle sloping, while below it is perpendicular, except 

 on the body-whorl in which the shell tapers anteriorly. There 

 are four distinct varices in all, the most anterior one bounding the 

 outer lip from outside; these are elevated, broad and round- 

 topped. Between every two varices, there are usually five broad 

 rounded ribs, indistinct near the upper suture and separated by 

 broad and shallow valleys. The whole surface is also spirally 

 grooved, with grooves numerous, narrow, at irregular intervals, 

 but arranged in such a way as to enclose broader spaces at certain 

 intervals. On this account the surface appears to be ornamented 

 with spiral threads and broader belts. These threads and belts 

 are again crossed by numerous fine longitudinal grooves, making 

 them appear granulate. Aperture subrhombic, with a shallow 

 posterior sinus. Inner lip callous, with many, close, unequal 

 transverse stria 3 , which become more separate towards the anterior 

 canal. Outer lip with coarse distant transverse folds within. 

 Canal moderate, with narrow opening and bent back. Rare. 



The number of whorls seems to be about eight or nine, but 

 the apex is broken. 



This species is closely related to Triton ; pyrum Linne (Syst 

 Conch. Cab. Mart. u. Chemn., vol. Ill, pt. 2, p. 211, pl. 59, 



