5. _Sorex v. vagrans_ originated in the Great Basin and arrived on the Pacific Coast after the last deglaciation of the Cascades and Sierra Nevada. 6. In _S. vagrans_, heterogonic growth is illustrated; the larger the skull, the larger the rostrum in proportion to the skull as a whole. 7. In the species _S. vagrans_, size and color vary geographically more than do other features. 8. The _S. ornatus_ group, _S. longirostris_, and _S. veraepacis_ had a common ancestor with _S. vagrans_, possibly in the Illinoian Age. 9. _S. vagrans_, the _S. ornatus_ group, _S. veraepacis_, _S. longirostris_, _S. palustris_, _S. bendiri_, and the _S. cinereus_ group, because of structural resemblances, should be placed in a single subgenus, _Otisorex_. _S. trowbridgii_, the _S. arcticus_ group, the _S. saussurei_ group, _S. merriami_, _S. fumeus_, and _S. dispar_, should be included in the subgenus _Sorex_. 10. _Sorex cinereus_ occurs with the medium-sized and large-sized _S. vagrans_ in the Rocky Mountains and in Canada, but does not occur with the smaller subspecies of _S. vagrans_, probably because competition between two shrews of like size excludes _S. cinereus_. TABLE 1--CRANIAL MEASUREMENTS OF SOREX VAGRANS ========================================================================== Catalog | | | | | | number or | | | | | Least | number of |Condylobasal|Palatal|Maxillary|Cranial|interorbital|Maxillary individuals| length |length |tooth-row|breadth| breadth | breadth averaged | | | | | | ------------+------------+-------+---------+-------+------------+--------- | _Sorex vagrans pacificus_, Orick, California. 8 av | 21.8 | 9.6 | 8.6 | 10.4 | 4.1 | 6.6 Max | 22.8 | 10.2 | 9.0 | 11.1 | 4.3 | 6.8 Min | 21.3 | 9.3 | 8.4 | 10.2 | 4.1 | 6.4 +------------+-------+---------+-------+------------+--------- | _Sorex vagrans yaquinae_, Newport, Oregon. 707 AW | 20.1 | 8.9 | 7.6 | 9.3 | 3.7 | 5.7 706 AW | 19.3 | 8.8 | 7.3 | 9.3 | 4.0 | 5.8 +------------+-------+---------+-------+------------+--------- | Mapleton, Oregon. 205273 USBS| 20.6 | 9.0 | 8.2 | 9.9 | 4.2 | 6.0 205270 USBS| 20.4 | 8.9 | 7.9 | 9.3 | 3.7 | 6.0 205272 USBS| | 9.2 | 8.3 | | 4.0 | 6.1 +------------+-------+---------+-------+------------+--------- | Vida, Oregon. 4 av | 19.5 | 8.4 | 7.5 | 9.2 | 3.6 | 5.5 Max | 20.3 | 8.8 | 7.9 | 9.5 | 3.7 | 5.7 Min | 19.3 | 8.2 | 7.3 | 8.9 | 3.5 | 5.3