180 AXEL A. OLSSON 



Crassatellites rudis Li, 1930, Bull. Geol. Soc. China, vol. 9, No. 3, p. 257, pi. 3, fig. 16.— 



Pilsbry, 1931, Proc. Acad. Nat. Sci. Philadelphia, vol. 83, pp. 429, 430, pi. 41, 



figs. 9, 10 (figured C. gibbosus). 

 Crassatellites (Hybolophus) gibbosus (Sowerby), Hertlein and Strong, 1946, Zoologica, 



vol. 31, pt. 3, No. 8, p. 103.— Hertlein and Strong, 1955, Bull. Amer. Mus. Nat. 



Hist., vol. 107, art. 2, pp. 181, 182. 



Shell of medium or large size, solid, usually stubby, elongately sub- 

 trigonal, the umbones convex and swollen, the anterior side convexly 

 rounded, the posterior side a trifle shorter, contracted and pointed at the 

 end. The flattened surface of the umbones is somewhat variable in size and 

 in the strength of its sculpture; usually there are about six strong, concentric 

 undulations present. Color of exterior is a deep brown or yellow, uniform or 

 with brown radial lines. Interior white with brown blotches. Periostracum 

 is a uniform ashy brown, usually worn off most specimens. 



An average specimen measures: length 58 mm.; height 43.4 mm.; 

 diameter 29.4 mm. Santa Elena, Ecuador. 



This species is represented as fossil by several closely allied forms; 

 some of which are a large size. 



Range — Gulf of California to northern Peru. Panama: Biicaro; San 

 Carlos; Panama City; Pearl Islands. Canal Zone: Venado Beach. Ecuador: 

 Santa Elena; Punta Blanca; Manta; Galeras; Esmeraldas. Peru: Tumbez; 

 Zorritos; Boca Pan; Mancora; Paita. 



Eucrassatella (Hybolophus) diqueti (Lamy) Plate 25, figure 2 



Crassatella undulata Sowerby, 1832, Proc. Zool. Soc. London, p. 56 "Puerto Portrero, 



Americae Centralis."— Reev«, 1843, Conch. Icon., vol. 1, Crassatella, pi. 1, figs. 



2a, 2b. Not C. undulata Lamarck, 1805, or C. undulata Say, 1824. 

 Crassatella diqueti Lamy, 1917, Jour, de Conchyl., vol. 62, No. 4, p. 2, 7 "He Ceralbo, 



Gulf of California. New name for Crassatella undulata Sowerby, not of 



Lamarck. 

 Crassatellites laronus E. K. Jordan, 1932, Nautilus, vol. 46, No. 1, p. 9. Near salt works 



at San Jose Island, Gulf of California.— E. K. Jordan, 1936, Contri. Dept. 



Geol. Stanford Univ., vol. 1, No. 4, p. 124, pi. 17, figs. 6, 7. 

 Crassatellites (Hybolophus) diqueti (Lamy), Hertlein and Strong, 1946, Zoologica, vol. 



31, pt. 3, pp. 102, 103. 



This is a relatively rare species, and it differs from E. gibbosa by its 

 longer form, less prominent, convex umbones and wider, less pointed, pos- 

 terior end. It is closely related to E. antUlarum of the Caribbean, having 

 the same rich, deep chocolate-colored interior. According to Lamy, distinc- 

 tion between the two forms is largely based on their geographic separation. 



Range— G\i\{ of California to Colombia (Hertlein). Mexico: Gulf of 

 California. Costa Rica: Puerto Potrero; Port Parker. Colombia: Gorgona 

 Island. 



Genus CRASSEfELLA Guppy. 1874 



Type species by monotypy, Crassinella martinicensis d'Orbigny. Recent, 

 West Indies. 



As indicated by Grant and Gale, 1931, Guppy first used the name 

 Crassinella in a list of species, in which only C. martinicensis was men- 

 tioned. A year later (1875), he indicated that the name was proposed as a 

 substitute for Gouldia C. B. Adams, 1847 (substitute for Thetis C. B. 



