

OXYCHONA. 189 1 



P. picta Born, v, 53. P. muscarum Lea., v, 54. 



venusta Gmel. globulosa Fer. 



sulphurosa Morel., v, 54. carnieolor Orb. 



L. tiara Martyn. v. subbrocheri Pils., v, 55. 



P. versicolor Born., v, 54. P. brocheri (Gut.) Pfr., v, 55. 



1 pictoria Perry. brocheroi Arango. 



? cincta Perry. 



Genus OXYCHONA Morch, 1852. 



Oxycliona MORCH, Cat. Yoldi, p. 14, type H. bifasciata. PILSBRY, 

 Man. of Conch., v, p. 128. MARTENS, Biol. Centr. Amer., Moll., p. 

 152. Geotrochus, Leptoloma, Corasia, Axina and Eurycratera of 

 authors. Leptarionta CROSSE & FISCHER, Moll. Mex. i, p. 253. 



Shell rather shining, thin and light colored, with spiral brown 

 bands, umbilicate or closed, the spire conic or depressed and merely 

 convex,the last whorl varying from acutely keeled to subangular. 

 Surface smoothish, often microscopically striate or granular. Aper- 

 ture oblique, the lip expanded or reflexed, rather thin, not toothed. 

 Type 0. bifasciata, pi. 45, fig. 8. (See also pi. 45, figs. 1,2, 0. costa- 

 ricensis. PI. 45, figs. 3, 4, 5, 0. altispira. PI. 45, figs. 9, 10, 0. 

 trigonostoma v. stolliana.') 



Animal (of 0. trigonostoma, pi. 45, figs. 9, 10) quite elongated, 

 the tail surmounted by a conspicuous serrate keel. 



Jaw (of 0. bifasciata, pi. 51, fig. 11), rather thin, arcuate, with 

 no median projection, having about 17 unequal ribs distributed 

 over its entire extent and denticulating the margin. 



Radula (of 0. bifasciata, pi. 51, fig. 10, central with 6 adjacent 

 laterals, fig. 9, 7th to 13th laterals, with one marginal, and fig. be- 

 low the latter, a lateral seen in profile) pavement-like, with v-shaped 

 rows of nearly similar teeth. Centrals with an oblong squarish 

 basal plate bearing one cusp springing from its middle, spreading 

 into a spatulate form, and projecting far over the posterior end of 

 of the basal plate on all sides. Laterals similar, but having the 

 entocone indicated by a notch in the basal plate near its posterior 

 angle, and bearing a minute basal ectocone. Outwardly, this ecto- 

 cone increases in size, and becomes split on the marginal teeth, 

 which are otherwise like the laterals. 



Distribution, Brazil to Mexico. Habits arboreal, as far a& 

 known. 



