96 PLEURODONTE. 



P. maiiueli Higg., v, 166. P. bogotensis Pfr., v, 176. 



manoeli Pfr. P. otostoma Pfr., v, 176. 



manseli Pfr.-Cless. stostoma Rv. 



Section Thelidomus Swainson, 1840. 



Thelidomus SWAINS., Malacology, p. 191, 192,330, type If. incerta 

 Fer. Not Thelidomus Swains., t. c., p. 228, 353,=larva-cases of Heli- 

 copsyche, (Neuroptera). Otala BECK and others, not of Schumacher. 

 -Pachystoma ALBERS, Die Hel., 1850, p. 125. Not Pachystoma 

 Guilding, Zool. Journ. 1828, p. 536. / Thelidonta SWAINS, t. c., 

 p. 194. 



Shell imperforate, globose-depressed, with few whorls, the last 

 deflexed in front, swollen beneath, carinated or rounded at the 

 periphery. Surface granulated, costulate-striate or decussated. 

 Aperture very oblique; peristome expanded, thickened within, the 

 lower margin straightened, with a plate-like callus inside. Type P. 

 incerta Fer. (See pi. 22, fig. 5, P. hma ; pi. 22, fig. 4, P. trinitaria}. 



Jaw arcuate, having 7-15 strong ribs, sometimes not denticulating 

 the lower margin (pi. 23, fig. 23, P. auricoma var. havanensis). 



Radula either with or without ectocones on central and inner 

 lateral teeth. Marginal teeth obtusely and obscurely bicuspid. PI. 

 23, fig. 22, P. auricoma var. havanensis. 



Animal having the sole undivided ; lateral edges without trace of 

 pedal grooves or margins. Sides of foot granulated, granules 

 arranged in vertical series in the middle, obliquely descending series 

 in front and behind; back irregularly granular, without longitud- 

 inal grooves. 



Genital system having the penis stout, with a flagellum at apex; 

 vas deferens and retractor muscle also inserted at apex, the latter 

 slender, and attached distally to the integument of the vestibule; a 

 small appendix sometimes present; no internal papilla, the opening 

 of the vas deferens being a simple orifice at the base of the flagellum 

 (pi. 23, fig. 19, showing opened penis and vestibule). Spermatheca 

 oval or oblong, enveloped in the folds of the uterus, its duct short, 

 bearing at the base a broad muscle connecting with the integument 

 of the body- wall near the genital orifice (pi. 23, fig. 21, v. m.~) ; ovo- 

 testis composed of one compact tuft of long creca, (pi. 23, figs. 19- 

 21, P. auricoma var. havanensis ; pi. 23, fig. 24, P. lima; pi. 23, fig. 

 25, P. aspera). 



