MPARISON OF CERTAIN MEASUREMENTS AND PROPORTIONS IN BUFO
MARMOREUS AND B. PERPLEXUS. (MEANS ARE GIVEN IN PARENTHESES BELOW THE
RANGES.)

+-------------------+------------+--+----------+------------+-----------+
| | | | |Tibia length|Head length|
| Species | Sex | N|Snout-vent+------------+-----------+
| | | | length | Snout-vent |Snout-vent |
| | | | | length | length |
+-------------------+------------+--+----------+------------+-----------+
| _B. marmoreus_ | Male |15|61.5-72.5 | 35.9-41.6 | 28.3-33.3 |
| | | | (65.2) | (39.0) | (31.6) |
+-------------------+------------+--+----------+------------+-----------+
| _B. perplexus_ | Male |20|50.0-59.0 | 33.7-38.1 | 26.4-31.1 |
| | | | (54.9) | (36.4) | (29.5) |
+-------------------+------------+--+----------+------------+-----------+
| _B. marmoreus_ | Female | 7|68.0-76.0 | 33.0-36.8 | 26.8-32.6 |
| | | | (70.7) | (34.7) | (29.6) |
+-------------------+------------+--+----------+------------+-----------+
| _B. perplexus_ |Female | 6|64.1-69.8 | 32.4-36.9 | 25.1-29.0 |
| | | | (66.8) | (35.5) | (27.5) |
+-------------------+------------+--+----------+------------+-----------+

Taylor (1943a:347) described _Bufo perplexus_ from Mexcala on the Rio
Balsas in Guerrero. Among the many paratypes are specimens from Tonola,
Chiapas, and Tehuantepec, Oaxaca. These apparently were referred to
_perplexus_ solely on the nature of the cranial crests. All of the
specimens examined during the course of the present study from the
lowlands of Veracruz and from the Pacific lowlands from Sinaloa
southward to Chiapas are referable to _Bufo marmoreus_; those from the
Balsas-Tepalcatepec Basin are referable to _Bufo perplexus_, as defined
above. Ten specimens from Chilpancingo, Guerrero (UMMZ 115352), do not
readily fit either species. Perhaps there is gene exchange between the
inland and coastal populations through the relatively low pass at
Chilpancingo, at the mouth of the Rio Balsas, and near the convergent
headwaters of the Rio Coahuayana and Rio Tepalcatepec in southern
Jalisco. If this can be demonstrated, then _Bufo perplexus_ would have
to be considered as a subsp