PACHYCHILUS, 451 
Hab. N. Guaremata: Rio de la Pasion (Salvin ®). 
E. Guaremata: Lagarto, near Zacapa (Sallé 4). 
W. GUATEMALA; Lake of Amatitlan, and in the Rio Michatoya, issuing from this 
Jake (Bocourt*); Rio Maria Linda (Morelet+); Paso Antonio, near Torola, 
at lower part of the Rio Michatoya (Stoll); Mirandilla, near Escuintla, Pacific 
coast (StoJ2). 
SaLvapor: Joya [an Guija?] (Sallé+). 
Cenrrau Nicaragua: Lake of Nicaragua (Von dem Busch *°). 
Also brought from Guatemala by Skinner? and others !°, Bocourt4 mentions too 
as a locality the Rio de las Vacas, the geographical situation of which is not known to 
me. Philippi! merely gives “Central America”; he received his specimens from 
Largilliert, a French conchologist. Salvin’s Guatemalan specimen, identified by 
Canon Tristram ® as Melanoides glaphyra, Morel., is now before me, and I am unable 
to distinguish it from P. largillierti. 
P. indifferens, Fisch. & Crosse, Journ. de Conch, xxxi. p. 25 (1891), and Miss, Scient. 
Mex., Moll. ii. p. 337, t. 50. figg. 8, 8a-c, from the Rio Motagua, E. Guatemala, looks 
very like young specimens of this species. Melania lacunata, Reeve, Conch. Icon. xii, 
Melania, t. 19. fig. 136 (copied by Brot, in Martini and Chemnitz, Syst. Conch.-Cab., 
ed. 2, Melaniaceen, p. 25, t. 3. fig. 4), locality unknown, is also perhaps one of the 
individual variations of P. largillierti. 
~ In this species the last whorl is relatively lower, with regard to the whole length of 
the shell, than in P. glaphyrus, Fischer and Crosse, which gives it a distinct appearance, 
resembling a Z'wrritella. 
_ Var. nodulosus,n. (Tab. XXYV. fig. 4.) 
A row of small knobs in the circumference of the last whorl; the preceding whorls smooth. Long. 61, 
diam. 24; apert. long. 22 millim. Anfr. superst. 8. 
Hab. W. Guatemata: Paso Antonio, in company with the normal form (S¢o//). 
The presence of small knobs on the shell in this variety indicates the affinity of 
P. largillierti with the sculptured species of Pachychilus, especially with P. lacustris ; 
in all other respects the specimen agrees with typical P. largillierti. 
Var. salvini. (Tab. XXVI. fig. 3.) 
Melanoides salvini, Tristram, P. Z. S. 1863, p. 413”. 
Melania salwini (sic), Brot, in Martini & Chemnitz, Syst, Conch.-Cab. ed. 2, Melaniaceen, p. 27”, 
Mechychilus salvini, Fisch. & Crosse, Miss. Scient. Mex., Moll. ii. p. 362”. 
Pachychilus subexaratus, Crosse & Fisch. Journ. de Conch, xxxix. p. 216 (1891) “; Miss. Scient. 
Mex., Moll. ii. p. 350, t. 52. fig. 6 - 
Narrowly turrite, whorls flatter, the last not very convex ; basal ridges distinct ; several spiral ridges also on 
the upper half of the last whorl in some specimens. 
57* 
