respondence and accession records at the National Museum
confirmed, beyond doubt, the validity of the locality data for
these specimens. Dr. Chaffee, the collector, frequently sent
specimens of plants and animals to the Museum from Durango and
Zacatecas; his home was in Lerdo.

_Size._--The largest specimen of _Gopherus flavomarginatus_ (USNM
61254) exceeds by more than 50 millimeters the length of the
largest known specimens of _G. agassizii_, and slightly exceeds the
length of the largest specimen of _G. polyphemus_ that I have
examined (USNM 51357, length of carapace 360 millimeters, a
specimen formerly kept at the National Zoological Park). _G.
polyphemus_ is the largest tortoise inhabiting the United States;
the maximum length of 343 millimeters given for the species by Carr
(1952:334) probably more closely approaches the true maximum in
free-living populations. _G. agassizii_ rarely attains a length
greater than 300 millimeters (Woodbury and Hardy, 1948:152-5). The
fact that representatives of the genus do not attain a larger size
in the United States may be due to the decimation of natural
populations by man for food and souvenirs.

There have been several indications that a large species of
tortoise existed in north-central Mexico. The Chihuahuan specimens
reported by Duges (248 and 202 millimeters long, respectively) rank
in size with the smaller paratypes of _G. flavomarginatus_; Duges
stated, however, that the species was said to attain a length of
one meter but that he thought such large size surely to apply to
another species.

Mr. Charles M. Bogert recently related to me two stories that are
here worthy of note. One of them, which Bogert learned from the
late Dr. Karl P. Schmidt, concerns a collector who was sent by the
Chicago Natural History Museum (then Field Museum) to Coahuila in
the early part of the century to obtain materials for a desert
exhibit. When the exhibit had been completed several decades later,
the collector, visiting the museum, inquired as to where the large
tortoises were that he had collected in Coahuila. Dr. Schmidt could
find no record of such tortoises and suggested that possibly they
had been confused with Galapagos tortoises (_Geochelone_). Dr.
Robert F. Inger is unable to locate the specimens or add anything
to the story. The col