38 



U.S. NATIONAL MUSEUM BULLETIN 260 



Table 1. — Characteristics of various genera and species in the hippomedon section 

 (Col. a: l = cuboidal and strongly ridged; 2 = button shaped with medium 

 ridging; 3 = button shaped, subovate and poorly ridged. Col. b: l=long 

 and distally expanded; 2 — long and rectangular; 3 = shortened and tapered 

 distally. Col. e: l=normal length; 2 = strongly shortened. Col. h: l=palm 

 transverse; 2 =palm oblique; 3 ^^palm obsolescent, extremely oblique. Symbols: 

 * = epistome strongly produced; + =positive, = negative, +0 = intermediate, 

 ? = questionable) 



> Species in process of description. 



