cies, both externally and cranially;
dorsal pelage dark; nasals broadly flared anteriorly (especially broad
in relation to nasal length); auditory bullae small; molariform
tooth-rows and incisive foramina long.

_Measurements (in millimeters)._--External measurements of the type
specimen, followed by those of another adult female (KU 72603), are:
Total length, 141, 145; length of tail-vertebrae, 24, 21; length of hind
foot, 20, 20; length of ear from notch, 11, 12. The type specimen
weighed 46.3 grams. Cranial measurements were taken in the manner
described by Wetzel (Jour. Mamm., 36:2-3, 1955) except that he did not
record the occipitonasal length. These cranial measurements of the type
and KU 72603 are: Occipitonasal length, 30.2, 29.8; condylobasilar
length, 27.2, 27.1; zygomatic breadth, 18.1, 17.9; lambdoidal breadth,
14.2, 13.8; length of nasals, 8.2, 8.3; breadth of nasals, 4.2, 4.0;
length of rostrum, 6.6, 6.6; breadth of rostrum, 6.1, 5.9; breadth of
upper incisors, 4.6, 4.2; length of maxillary tooth-row, 8.5, 8.4;
length of incisive foramen, 5.8, 5.5; interorbital breadth, 3.1, 3.5.

_Comparisons._--From _Synaptomys cooperi gossii_ (specimens from eastern
Nebraska and eastern Kansas, including one topotype), _S. c. relictus_
differs in: Dorsal coloration, in comparable pelages, darker, venter
lacking buffy tinge; skull averaging larger in all cranial dimensions
(except rostral length, which is approximately the same), especially
breadth of upper incisors and length of molariform tooth-rows; nasals
broader anteriorly; auditory bullae nearly equal in size, thus
relatively smaller. From _Synaptomys cooperi paludis_ (holotype and
paratypes) of Meade County, Kansas, _S. c. relictus_ differs in: Skull
averaging smaller in all cranial measurements except rostral length and
breadth of upper incisors, which are approximately the same, and breadth
of nasals, length of incisive foramina and length of molariform
tooth-rows, which measure more; nasals relatively (48 per cent of length
of nasals) as well as actually broader anteriorly; anterior border of
zygomatic plate more concave; auditory bullae smaller; infraorbital
foramina larger when viewed anterolaterally. _S. c. relictus_ closely
resembles _S. c. paludis_ in color and external proportions.

_Remarks._--The total population of _Synaptomys cooperi relictus_ may be
small because the only suitable habitat known to me for these mice is
the dense, grassy area, approx