194 AXEL A. OLSSON 



Neocyrena mexicana (Broderip and Sowerby), Fischer and Crosse, 1894, Miss. Scient. 

 a Mexique et TAni^rigue oentrale, sept parte, tome II, pp. 637, 638, pi. 70, 

 figs. 7, 7a, 7b. 



This is a smaller, more ovate and generally a more solid species than 

 P. notabilis. Color white, tinted irregularly with purple. The periostracum 

 is dark brown or green, irregularly wrinkled and generally destroyed over 

 the umbones. 



A more northerly species than P. notabilis and apparently restricted 

 to the coast of Mexico. A specimen in the U. S. National Museum Collection 

 at Washington measures: length 31.8 mm.; height 25.6 mm.; diameter 20.2 

 mm. 



Range — Pacific Coast of Mexico. 



Subgenus PSEUDOCYEEIfA Bourguignat, 1854 

 Type species by monotypy, Cyrena maritima d'Orbigny, 1842. Recent, 



Cuba and Florida. 



(C cubensis Prime, 1865, a replacement name for maritima d'Orbigny 



but not necessary.) 



The shell is generally small or medium size, ovate to elongate trigonal, 

 usually thin, marked with concentric growth line striae, white or more 

 or less tinted with purple, and covered with a thin, adherent, brown or 

 olive-green periostracum. The ligament is external, the hinge provided 

 with three cardinal teeth in each valve (the right middle and posterior 

 and the left middle and anterior teeth bifid) and anterior and posterior 

 lateral teeth equidistant from the beaks. Pallial sinus short and poorly 

 defined, crowded against the posterior adductor scar. 



A group of small species of the Caribbean and Floridian region. 



Subgenus EGETA H. and A. Adams, 1858 

 {Anomala Deshayes, 1855, not of Hiibner, 1816; Samouille, 1819; 



Stephens, 1829). 



Type species by tautonomy, Cyrena anomala Deshayes. Panamic- 



Pacific. 



Shell ovate to high, trigonal-cordate, inequilateral, the beaks placed 

 nearer the anterior end, the posterior side rounded or pointed at the end. 

 Valves are strongly inflated. Surface marked mainly with fine, concentric 

 growth lines and covered by a dark brown or olive-green periostracum, 

 finely wrinkled or fuzzy. Pallial line is nearly entire or with a small, narrow 

 sinus crowded against the posterior adductor scar. 



The name Egeta was proposed by the Adams brothers as a replacement 

 of Anomala Deshayes, several times preoccupied. Deshayes did not give a 

 description of Anomala, the name being shown in parenthesis as a sub- 

 genus of Cyrena. J. P. E. Morrison has suggested that Egeta should be con- 

 sidered a synonym of Geloina Gray, 1840 (type species, Cyrena zey lanica 

 (Chem.), Lamarck), of the Indo-Pacific but since Egeta was proposed for 

 American species, the name seems preferable in this instance. 



rolyiuesoda (Egeta) anomala (Deshayes) Plate 27, figure 7: 



Plate 33, figures 7, 7a 



Cyrena anomala Deshayes, 1855, Proc Zool. Soc. London for 1854, p. 21 Bay of Caracas. 



