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Humeroradial
| Intermembral
| | Crural
| | | Tibioradial
| | | | Femorotarsal-
| | | | | metatarsal
| | | | | Cranial
| | | | | |
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ordii 144.5 57.2 127.75 60.55 88.4 63.4
microps 138.5 56.17 132.3 57.27 90.95 60.8
panamintinus 146.1 55.3 132.0 57.5 90.5 60.8
agilis 147.0 55.05 133.65 57.25 94.55 62.65
heermanni 142.9 54.2 135.9 55.35 92.2 60.93
ingens 142.9 54.1 130.6 56.2 89.65 66.2
spectabilis 140.9 53.05 133.9 54.2 95.6 64.6
phillipsii 163.4 55.05 137.85 58.97 101.5 64.5
merriami 160.75 53.85 137.5 57.35 99.75 63.9
nitratoides 155.0 54.1 137.4 57.0 98.25 65.5
deserti 149.5 53.4 139.4 54.9 96.6 67.6
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The right kidney is variable in position in reference to the left. In
all species the right kidney lies anterior to the left but in some, _D.
deserti_ and _D. ingens_, it is markedly anterior.
In _Dipodomys agilis_, _D. merriami_ and _D. deserti_ there are small to
large patches of lymphoid tissue on the caecum. These patches were not
noted in any of the other species examined and I do not know their
function. In the three above mentioned species, however, the large
intestine is shorter in proportion to the small intestine than in any
other species except _D. heermanni_ (see Table 2) and with the exception
of _D. heermanni_, _D. venustus_ and _D. ordii_ the actual measurements
are less.
Inasmuch as little is known of the food habits of the various species of
kangaroo rats, any ascription of adaptive significance to the varying
proportions of the digestive system would be only speculative.
Midgley (1938) describes the visceral anatomy of _D. ordii_ and _D.
microps_. Except for the differences here noted the description of the
viscera as given by Midgley (_loc. cit._) applies to the rest of the
species studied.