BIRDS OF NORTH AND MIDDLE AMERICA. 57 



Family APHRIZID^. 



THE SURF BIRDS. 



'^Strepsilasinx Sclater and Salvin, Nom. Av. Neotr., 1873, 143 (includes Arena- 



riidae). 

 "^Sirepsilidx Baird, Brewer, and Ridgway, Water Birds X. Am., i, 1884, 107, 



118. (includes Arenariid^e). 

 =Aphrizinae Coues, Key N. Am. Birds, 2d ed., 1884, 605. — American Ornithol- 

 ogists' Union, Check List, 1886, 164; 3rd ed., 1910, 131. 

 '^Aphrizidx Coues, Key N. Am. Birds, 2d ed., 1884, 605, in text (includes 



Arenariidse). — American Ornithologists' Union, Check List, 1886, 164; 



3rd ed., 1910, 131 (includes Arenariidse). — Ridgway, Orn. Illinois, ii, 1895, 



18, 20 (includes Arenariidiie). 

 =Aphrizidse. Shufeldt, Journ. Morph., ii, no. 2, Nov., 1888, 338. — Oberholser, 



Outl. Classif. N. Am. Birds, 1905, 2. 



Medium-sized Charadrii with a well-developed though small hal- 

 lux, anterior toes margined laterally by a conspicuous tumid mem- 

 brane or pad, acrotai*sium (but not planta tarai) regularly trans- 

 versely scutellate, bill plover-like (swollen distally, contracted 

 proximall}?-), ^nd tip of tail emarginate. 



The Aphrizidfe are medium-sized plover-like birds, more nearly 

 related to the Turnstones (Arenariidae) than to the true plovers 

 (Charadriidse) though much nearer the latter in the form of the bill. 

 With the Arenariida? the Aphrizidee agree in the stout legs and feet, 

 well-developed hallux, and scutellate acrotarsium, though differing, 

 besides in the form of the bill, which is very unlike in the two groups, 

 in tlje emarginate tail, reticulate instead of scutellate planta tarsi, 

 and strongly developed lateral tumid membrane to the anterior toes. 



The Surf Birds comprise a single monotypic genus, restricted in 

 its range to the Pacific coast of America. 



The single genus representing this family has sometimes been 

 placed with the Charadriidae and sometimes with the Arenariida^, but 

 is quite distinct from either. P>om the former the Aphrizidse differ 

 in the completely cleft anterior toes, with distinct lateral serrated 

 membrane; well-developed and nearly incumbent hallux, robust feet 

 (which are even stouter than those of the Arenariidse), and emarginate 

 tail. The differences between Aphrizidfe and Arenariidse are equally 

 marked and may be concisely stated as follows: 



a. Bill distinctly convex terminally and constricted subterminally, neither the max- 

 illa nor mandible depressed terminally; lateral gi-ooves of bill extending to base 

 of convex terminal portion; legs and feet much more robust, the lateral mem- 

 brane of anterior toes more strongly developed, distinctly roughened or serrate; 

 transverse scutella of acrotarsium broken into hexagonal scales on upper and 



lower portions; planta tarsi reticulate; tail emarginate Aphrizidse. 



aa. Bill tapering to the acute tip, not constricted subterminally, both maxilla and 

 mandible flattened at tip; lateral grooves of bill extending not more than half 

 way to tip; legs and feet more slender, the lateral membrane of anterior toes 

 less developed, smoother; transverse scutella of acrotarsium continuous; planta 

 tarsi scutellate; tail truncate Arenariidae. 



