PACHYCHILUS. 461 
C. Subgen. Oxymetania. 
Oxymelania, Fischer & Crosse, Miss. Scient. Mex., Moll. ii. pp. 328, 366 (1892). 
More or less slenderly elongate ; upper whorls not eroded; peristome very thick, 
swollen, somewhat expanded. 
18. Pachychilus graphium. 
Melania graphium, Morelet, Test. Noviss. i. p. 26 (1849)*; Hanley, Conch. Miscell. Melania, t. 4. 
fig. 35°. 
Pachycheilus graphium, H. & A. Adams, Gen. Moll. i. p. 298 (1854) °. 
Pachychilus graphium, Fisch. & Crosse, Miss. Scient. Mex., Moll. ii. p. 382, t. 51. figg. 2, 2a‘. 
Pachychilus cumingii, Lea, P. Z. 8. 1850, p. 179°; Ann. & Mag. Nat. Hist. (2) ix. p. 58 (1852) ° 
(repetition). 
Melania renovata, Brot, Matériaux fam. Mélaniens, i. p. 43 (1862) 7; in Martini & Chemnitz, Syst. 
Conch.-Cab. ed. 2, Melaniaceen, p. 41, t. 5. fig. 5°. 
Pachychilus gracilis, Tristram, P. Z. S. 1863, p. 413°. 
Melania gracilis (Tristram), Brot, loc. cit. p. 42 °°. 
Pachychilus tristrami, Fisch. & Crosse, loc. cit. p. 369". 
Hab. N. Guatemata: Lake of Peten (Salvin 9 10 11); streams of Vera Paz (Morelet '); 
Rio de Tactic (Morelet +); Sabo, Alta Vera Paz (Champion) ; Chiacam, near 
Lanquin, on the Cahabon River, an affluent of the Polochic (Champion) ; Coban *, 
in large rivers (Lea *%). 
Centra GuatemaLa: Huehuetenango (v. Lhering, in litt.); Salina La Magdalena, at 
Sacapulas, Department of Quiché, 7000 feet above the sea (Stol/). 
The specific name graphium is Latin, from the Greek yga¢eior, a “ style” or “ pencil.” 
Var. reductus. 
Melanium graphium (Morelet), Reeve, Conch. Icon. xii., Melania, t. 21. fig. 150"; Brot, in Martini 
& Chemnitz, Syst. Conch.-Cab. ed. 2, p. 41, t. 5. fig. 4. 
Pachychilus graphium, var. reducta, Fisch. & Crosse, loc. cit. p. 3833“. 
Somewhat broader. | 
Hab. N. Guatemata: Vera Paz (Morelet 171%). 
Var. transcendens. | —_ 
Melania cumingi, Reeve, loc. cit. fig. 149 (1860) *’ (nec M. cumingi, Lea, 1850, from the Philippines). 
Pachychilus graphium, var. transcendens, Fisch. & Crosse, loc. cit. p. 333, t. 50. figg. 7, 7a. 
Of larger size. 
Hab. CentraL GuatemMaLA: San Miguel Uspantan, Dept. Quiché, in affluents of the 
Rio Usumacinta (Stoll 1%). 
I have specimens of this variety from Dr. O. Stoll himself, and it is mentioned in 
his work on Guatemala (p. 382). Schneider, who is referred to by Fischer and Crosse 16 
* Lea gives “ Copan,” probably a mistake for Coban, see anted, p. 444. 
