PLANOBBIS. 399 
a diameter of 8 and a height of 2¢ millim. to his Vera Cruz examples. Those from 
Escuintla, Guatemala, average 5 millim. in diameter, 14 in height, and 12 in the 
diameter of the aperture; they are of a shining brown colour. Tristram‘ gives, for 
P. doubilli, 9 millim. in diameter and 23 in height: neither Fischer and Crosse nor 
I have seen his specimen; but the French authors mention it as a distinct species, 
observing at the same time that they cannot find any important difference between it 
and P. obstructus, and that P. doubilli may be regarded as a large variety of that 
species. As Strebel mentions examples of nearly the same size from Vera Cruz, it 
cannot be admitted even as a geographical variety. 
The specimen from Panama in Albers’s collection is labelled P, dentatus, Gould, a 
MS. name mentioned by H. & A. Adams (Gen. Moll. ii. p. 265); but it is 
impossible to say whether this name is correctly applied. 
23. Planorbis dentiens. 
Planorbis dentiens, Morelet, Test. Noviss. i. p. 18 (1849) '. 
Planorbula dentiens, Fisch. & Crosse, Miss. Scient. Mex., Mollusca, ii. p. 80, t. 33. figg. 7, 7 a, b, d’. 
Hab. British Honpuras: Belize, in marshes (Morelet } 2). 
Var. edentula. 
Planorbis cannarum, Morelet, loc. cit. p. 16°. 
Planorbula dentiens, var. edentula, Fisch. & Crosse, loc. cit. pp. 80, 81, t. 34. figg. 6, 6 a-c ‘. 
Hab. British Honpuras: Belize, in marshes (Morelet 3+). 
| . Doubtful Species of Planorbis. 
S. Clessin, in his Monograph of this genus [Martini & Chemnitz, Syst. Conch.-Cab. 
ed. 2, Limneiden (1878)], describes and figures several species which he had received 
from A. Morelet’s collection, merely giving ‘? Central America” or no indication 
of locality at all; but as Morelet also collected in Cuba, and in the neighbouring 
Isla de Pinos, and Clessin himself included Cuba in his term ‘‘ Central America,” 
these species cannot be admitted here without further confirmation. Those which 
I have been able to identify satisfactorily with known Central-American forms are 
mentioned in the preceding pages; the rest will be briefly mentioned here, as it 
is just possible that they have been found within our limits. ie 
Planorbis colon, Clessin, loc. cit. p. 209, t. 82. fig. 3: diam. 20, alt. 5°0 millim. ; 
whorls 5-6. This species approaches the rather compressed forms of P. caribeus, 
but it has the left side deeply concave and apparently without an angular line 
even in the first-formed whorls. 7 
Planorbis paucispiratus, Clessin, loc. cit. p. 223, t. 83. fig. 8: diam. 14, alt. 7 millim. ; 
with 3 rapidly increasing whorls (given by A. Morelet). In Dunker’s collection, 
which was at the disposal of Clessin when he worked at his Monograph, there is 
