24 NON-MARINE MOLLUSCS OF SURINAM. 
agreeing very much with specimens of P. venezuelensis 
Marts., other ones with specimens of P. striata Shuttl. 
(non d’Orb.) both of them from the Berlin Museum, and 
identified by the late Prof. von Martens himself. There 
are however also specimens, gradually connecting these 
forms with the majority of specimens, which agree with the 
P. rivalis of several authors. — von Martens says that P. ri- 
valis Sow., striata Shuttl., and venezuelensis are very closely 
related; I should not wonder if a very great quantity of 
specimens from various localities of South-America and 
the Antilles will give evidence that they all represent 
only one and the same species, whose shell is liable to a 
considerable variability. 
There is existing in literature some confusion as regards 
the name of this species. Many authors consider sivalis 
Sow. being identical with rivalis Mat. et Rack. The latter 
however is a European mollusc, related to, or probably the 
same as P. fontinalis L.; P. rivalis Sow., according to the 
rules of nomenclature, must change its name in P. sower- 
byana d’Orb. 
57. LYMNAEA spec. 
Kappler, 1887, p. 204. Surinam. 
As far as I know, no species of Lymnaea is reported 
from the Guyana’s or Venezuela. However it is not un- 
likely this genus, occurring in Brazil and on the Antilles, 
will be found also in northern South-America. 
* 58. AURICULASTRA PELLUCENS Mke. 
Auricula pellucens, Menke, Synopsis Moll., Ed. Il, 1830, p. 134. 
Auriculastra pellucens Mke, Kobelt, Syst. Conch. Cab., Ed. 
nov., Band I, Abt, 16, 1901,, p. 101, T. 45, Emo mts 
Surinam. Voltz. 
Surinam. Bolten, 1910. 
Nickerie. ten Kate. 
Environs of Paramaribo. van Heurn, 1914. 
Schepman, 1887, pp. 156, 164. Nickerie. 
* 59, MELAMPUS COFFEA L. 
Bulla coffea, Linné, Syst. Nat., Ed. X, 1758, p. 729. 
Notes from the Leyden Museum, Vol. XXXVI. 
