This paper describes and illustrates 91 species of Recent Ostracoda from the Gulf of California; 42 species are newly described, 34 are previously described, and 15 are not given specific assignment.
Based on the collections studied here the following distributional associations of Gulf of California Ostracoda are noted:
1. Species generally distributed in the Gulf but occurring mainly near-shore in water less than 50 fathoms deep and on sandy mud or sand bottoms; or if present offshore, occurrences are in central and northern parts of Gulf in water up to several hundred fathoms deep and on sandy mud or mud bottom: 35 species.
2. Species restricted to nearshore localities in water less than 50 fathoms deep, on sand or sandy mud bottoms, and on both sides of Gulf: 17 species.
3. Species restricted to eastern marginal part of Gulf in water less than 50 fathoms deep and on sand, sandy mud, or muddy sand bottom: 7 species.
4. Species restricted to western marginal part of Gulf in water less than 50 fathoms deep, on sand, sandy mud, or muddy sand bottom: 15 species.
5. Species restricted to southern part of Gulf, offshore, in water down to 1,655 fathoms and on mud bottom: 1 species.
6. Species restricted to northern part of Gulf, offshore, in water down to 488 fathoms and on mud bottom: 3 species.
7. Species restricted to southwestern part of Gulf, nearshore, in waters less than 50 fathoms, and on sand or sandy mud bottom: 4 species.
8. Species restricted to southeastern part of Gulf, nearshore, in water less than 50 fathoms, and on sand or sandy mud bottom: 4 species.
9. Species characteristic of nonmarine or brackish water environments but in some instances found in offshore bottom sediments as a result of having been rafted on floating vegetation or other process of transportation: 7 species.
The possible sources of the ostracode fauna and migration paths of the species are briefly discussed.