ANCYLUS. 401 
Geographical distribution universal ; comparatively more numerous in species in 
North America than elsewhere. 
ComPaRATIVE TABLE OF THE SPECIES OF AWCYLUS. 
Nomen. Figura. Sculptura, Apex. Long.| Lat. | Alt. Patria. 
: ae . mm. | mm. | mm. 
sallei, Bourg. ...... elliptica, obtuse | radiatim costulata. | obtusus, in $-3long.,| 32-5 | 2 3 | E. Mexico. 
conica. paulum dextrorsus. 
papillaris, v. Mart. . elliptica vel sub-| microscopice radi-| obtusus, in ¢ long.,| 4-5 | 8 13 | N.W. Mexico. 
ovalis, depresse}  atim striatula. dextrorsus. 
conica. 
excentricus, Morel..| ovato-oblonga, de- | levis. acutiusculus, in 3-2} 7 43 ? | Yucatan, N. Gua- 
presse conica. long., dextrorsus. temala, EK. Ni- 
caragua. 
——, var. biolleyi,| ovato-oblonga, de- . acutus, in ¢ long.,| 5-53 | 38 2 | Centr. Costa Rica. 
v. Mart. presse conica, dextrorsus. 
postice compressa. 
» var. pittieri, ovato-oblonga, de- ” obtusiusculus, in 44 3 14 | S.W. Costa Rica. 
v. Mart. presse conica, % long., dextrorsus. 
postice rotundata. 
1. Ancylus sallei. 
Ancylus sallet, Bourguignat, Aménités Malac. ii. p. 82 (Rev. et Mag. Zool. 1857, p. 16)*; Spicilegia 
Malac. p. 2317; Binney, Land and Freshw. Moll. N. Am. ii. p. 142°; Strebel, Beitr. Mex. 
Land- und Siissw.-Conch. i. p. 68, t. 4. fig. 35°; Fisch. & Crosse, Miss. Scient. Mex., 
Mollusca, ii. p. 88, t. 80. figg. 17, 17a, 5°; Clessin, in Martini & Chemnitz, Syst. Conch.- 
Cab. ed. 2, Ancylinen, p. 25, t. 6. fig. 9 (copied from Strebel) °. 
Radiately striate and with a few concentric ridges ; apex very blunt, at about: ? or 3 of the length, somewhat 
to the right. 
Long. 5, lat. 2 (32), alt. 14 millim. (Bourguignat). 
fp Ry an 23s » 13  ,, (Strebel). 
Hab. E. Muxico: Laguna larga de Toxpan, near Cordova, on pieces of rotten wood 
(Sallé1235); Vera Cruz, within the shell of an Ampullaria (Strebel * 6), 
It is not quite certain that the shells obtained by Sallé and Strebel belong to 
one and the same species, as the measurements given by the French and German 
authors do not accord; moreover, the apex in Fischer and Crosse’s figure® is placed 
at three-fourths of the length, and in that of Strebel‘ at three-fifths of the length. 
Bourguignat’s measurement of the breadth, however, does not agree with Fischer and 
Crosse’s figure, as in the latter the breadth is somewhat more than half the length, 
about 2 and not 2 of it. Strebel*, in his description of the shell, uses the terms 
“before” and “left” in a contrary sense, these portions, in regard to the position of 
the animal, being really “‘ behind” and “right.” 
According to Bourguignat, A. sal/et is also found in Cuba. 
BIOL. CENTR.-AMER., Terr. and Fluviat. Mollusca, August 1899. 51 
