On the basis of the evidence presently available, we are reluctant to follow Sutton (1950:136) in assigning breeding birds from the Gulf coastal region to _C. s. inornatus_, a name otherwise applied to a population of birds breeding inland, in northwestern North America south to central Utah and Colorado and east to South Dakota (and formerly to western and southeastern Minnesota and Iowa; see A.O.U. Check-list, 1957:190). The intermediate characters of birds breeding in coastal Texas and Tamaulipas probably represent not the results of actual genetic intermixing of the two named populations but, rather, an adaptive response of the eastern coastal stock (_C. s. semipalmatus_) to environmental modalities distinct from those operating elsewhere within the range of the eastern coastal population or on the inland population. Accordingly, we tentatively use the name _C. s. semipalmatus_ for our Tamaulipan specimens, realizing that the patterns of geographic variation in the species do not lend themselves well to taxonomic treatment by the trinomial nomenclatural system. The need for a comprehensive analysis of geographic variation in this species, based, if possible, on proper segregation of age classes along the lines followed by Pitelka (1950) for _Limnodromus_, is obviously indicated. PLATE 5 [Illustration: Map of coastal Tamaulipas, showing the barrier island and localities mentioned in text. Stippled areas are extensively marshy.] PLATE 6 [Illustration: FIG. 1.--_Croton_ and _Fimbristylis_ on stabilized dunes; the Laguna Madre and surrounding alkaline flats and clay dunes are visible in the background. Habitat of Road-runner, Ord kangaroo rat, and keeled lizard.] [Illustration: FIG. 2.--Active dune near Camp 1. Other active dunes can be seen in the background, in the right foreground is a clump of _Croton_, and in the left foreground is a small clump of _Fimbristylis_. Habitat of Road-runner, Ord kangaroo rat, and keeled lizard.] =_Arenaria interpres morinella_= (Linnaeus): Turnstone.--Approximately 40 individuals were noted along the beach from July 6 to 10, mostly in small groups; the largest flock included 15 individuals. Specimens (5): [M], 38931, testis 4 × 1 mm., moderately fat, 107 gm., 4 P old; [M], 38932, testis 3 × 1 mm., moderately fat, 103 gm., molting; 75 miles south of Washington Beach, July 8. Male, 38928, testis 2 mm., 111 gm., 3 P old; [M], 38929, testis 3 mm., moderately fat, 106 gm., 6 P old; [M], 38930, testis 2.5 mm., moderately fat, 108 gm., 6 P old; Camp 2, July 9.