PLEURODONTE. 99 



Jaw strong, arcuate, sculptured with high, rather narrow ribs 

 crenulating the upper margin only, or both margins (pi. 23, fig. 16, 

 P. dilatata). In P. angulata Binney found 7 ribs on the jaw ; in 

 crispata 10 ribs. In P. dilatata we find 9-11 ribs, which crenulate 

 the upper but not the lower margin, the latter having a slight 

 median projection. 



Dentition : Central and lateral teeth having stout, longmesocones 

 projecting beyond the basal-plates ; ectocones represented by a lateral 

 bulging of the reflection of the cusp, or by distinctly developed cut- 

 ting-points. Marginal teeth having the mesocones stout, oblique, 

 blunt or sub-bifid, the ectocone simple, minute (pi. 23, fig. 18, P. 

 angulata ; pi. 23, fig. 17, P. dilatata). 



Genitalia : Female system presenting no accessory organs ; the 

 spermatheca short, globular, situated upon a long duct. Penis stout, 

 cylindrical, having a large globular appendix near its base. At its 

 apex is situated a short, curved, obtuse flagellum, near the base of 

 which is inserted the vas deferens, and a short teat-like organ which 

 is solid and fleshy, not perforated or hollow. No retractor muscle 

 seen. When opened lengthwise the walls of the cavity of the 

 appendix and of the penis are seen to be longitudinally folded (fig. 

 14), the folds disappearing in the upper part of the penis-cavity. 

 The upper part of the cavity is occupied by a large, free, pestle- 

 shaped penis-papilla, perforated at the end, the perforation leading 

 to the cavity of the vas deferens and flagellum the latter being 

 corrugated inside (pi. 23, fig. 13, 14, P. dilatata). 



Distribution : Hayti. 



P. angulata Fer., v, 69. P. dissita Dh., v, 71. 



infiata Dh. P. undulata Fer., v, 72. 



acutangula Beck. lineolata Lam. 



P. obliterata Fer., v, 69. v. crispata Fer., v, 72. 



P. angustata Fer., v, 70. P. dilatata Pfr., v, 73. 

 P. dominicensis Pfr., v, 70. 



extensa Pfr. not Mull. 



Section Luquillia Crosse, 1892. 



Luquillia CROSSE, Journ. de Conchyl. 1892, p. 19, type if. luquil- 

 lensis. Lelostoma SWAINS. Malacol., p. 328 (preoc.), 1840. 



Shell imperforate, solid, subglobose with rather conoidal spire, of 

 about 5* whorls, the earliest 2 forming the large, coarsely gran- 



