OXYSTYLA, MEXICO, ETC. 121 



brown-edged, parietal callus brown. Last whorl puckered a little 

 below the suture. 



Alt. 49, diam. 29, length of aperture 23-24 mill. 



Alt. 43, diam. 25, length of aperture 20 mill. 



Nicaragua (Levy, Gabb). N. W. Costa Rica : Quebrada (ravine) 

 del Vijaqual, in the valley of the Rio Saveyre, at an elevation of 150 

 metres (Pittier); woods at Terraba, at an elevation of 250 to 270 

 metres ; Alto de Mano Tigre, 690 metres ; JSoruca, at an elevation of 

 450 metres ; El Pozo, 50 metres, common in clear primeval woods 

 (Pittier); Costa Rica, without nearer indication of locality (Carmiol, 

 in Berlin Museum). 



Helix undata FERUSSAC, Hist. Nat. Moll. Terr, et Fluv., pi. 115, 



f. 3, 5 (living animal); Tabl. Syst., p. 48, no. 337 (part) Bulimus 



(Orthalicus} zebra (Mull.) BECK, Index Moll., p. 59. Orthalicus 

 zebra (Mull.) SHUTTL., Notitiae Malac, p. 61, pi. 8, f. 3, 4. PFR., 

 Monogr. Helic. Vivent. iv, p. 589. H. & A. ADAMS, Gen. Moll., 



pi. 75, f. 6 (living animal, copied from Ferussac) Orthalicus prin- 



ceps MORCH, in Malak. Blatt. vi, p. 112 (1859) Orthalicus melano- 

 cheilus (Val.), FISCH. & CROSSE, Miss. Scient. Mex., Mollusca i, p. 

 458 (in part), pi. 18, f. 5, 5a. Ortalichus tricinctus MARTENS, 

 Biol. Centr. Amer. pp. 180, 185, pi. 11, f. 8 (1893). 



" This species has been confounded with the North Mexican 0. 

 melanocheiluSj from which it differs in the more ovate and thinner 

 shell, and the ordinarily well-defined three dark brown spiral bands." 

 It is smoother than most specimens of the three-banded form of 0. 

 maracaibensis, with fewer black varices, and a shorter body-whorl 

 and aperture. In 0. undata var. floridensis the body-whorl and 

 aperture are larger. 



Typical 0. tricincta might well be considered a distinct species 

 were it not that among the specimens collected by Gabb in Nicaragua 

 there is one (pi. 17, fig. 18) showing faintly but unmistakably the 

 longitudinal flames of O.ferussaci, though with all the other features 

 of the tricincta with which it was found associated. This causes me 

 to consider tricincta an extreme form of ferussaci, which in another 

 direction merges into princeps. 



I have also before me two specimens labeled " Nicaragua," col- 

 lected by Gabb, in one of which the three bands are faintly visible 

 on close inspection, the other totally wanting them, being marked 

 with dark varices only. 



