82 DRYM^EUS, MEXICO AND CENTRAL AMERICA. 



Hist. Nat. des Anim. sans Vert., ed. 2, viii, p. 279 PFR., Monogr. 



Helic. Vivent. ii, p. 176. REEVE, Conch. Icon, v, Bulimus, pi. 23, 

 fig. 145 TATE, Amer. Journ. Conch, v, pp. 152, 156 (1870). 

 Bulimus (Mesembrinus) discrepans ALBERS, Die Helic. ed. i, p. 158 

 PFR., in Malak. Blatt. ii, p. 158 (1855) Orthalicus (Mesem- 

 brinus) discrepans H. & A. ADAMS, Gen. Rec. Moll, ii, p. 157. 

 Bulimulus (Liostracus) discrepans FISCH. & CROSS E, Miss. Scient. 

 Mex., Mollusca, i, p. 503.. Otostomus discrepans VON MARTENS, 

 Biol. Centr. Amer., p. 230. 



Allied to D. livescens and some forms of D. multilineatus, but thin- 

 ner than the latter, with fewer whorls and somewhat different color- 

 ation. Some specimens show a narrow spiral band revolving a little 

 above the middle on the ante-penultimate and next earlier whorls. 

 Specimens from Guanacasta examined by Dr. von Martens are 

 smaller, measuring: Alt. 16, breadth 8, and aperture 9 mill. Sow- 

 erby's type from Conchagua measured : Alt. 0.7, diam. 0.33 inch. 



D. SEMIPELLUCIDUS (Tristram). PI. 4, figs.. 71, 72, 73. 



Shell imperforate, oblong-conic, fragile, shining, semipellucid, 

 white, marked with sparse opaque streaks. Spire conic, acute: suture 

 deep. Whorls 6, convex, the last a little longer than the spire, in- 

 flated, rounded at base ; columella vertical, straightened. Aperture 

 slightly oblique, angulate-oval ; peristome thin, the right margin very 

 little expanded, columellar margin shortly reflexed. 



Alt. 18, diam. 8 mill. (Tristr.) 



Guatemala (Salvin). N. W. Costa Rica: Guanacasta, in the Bay 

 of Salinas (Pittier). N. E. Costa Rica : Puerto Viejo, on the Rio 

 Sarapiqui (Biolley). Central 'Costa Rica: Alajuela (Orosco). 



Bulimus semipellucidus TRISTRAM, P. Z. S., 1861, p. 230, pi. 26, 

 fig. 8. PFR. Monogr. Helic. Vivent. vi, p. 22 Bulimulus (Liostra- 

 cus) semipellucidus FISCH. & CROSSE, Miss. Scient. Mex., Mollusca, 

 i, p. 507. Otostomus semipellucidus MARTENS, Biologia, p. 236, pi. 

 15, f. 10. 



" I am rather inclined to think that this is an albino variety of 0. 

 discrepans. The specimen from Guanacasta, from which our figure 

 is taken, has a few brownish oblique stripes on the whorl before the 

 last, whereas in all respects it agrees with the Rev. H. B. Tristram's 

 description and figure ; but as the whorls are a little more convex 

 than in 0. discrepans, and the umbilical cleft completely closed, I 



