372 AXEL A. OLSSON 



Islands), USNM 588410. Colombia: Isla del Gallo. Ecuador: Santa Elena. 

 Peru: Paita. 



Cnmingia mutlca Sowerby Plate 66, figure 4 



Cumingia mutica Sowerby, 1833, Proc. Zool. Soc. London, p. 34. — Sowerby, 1873, Conch. 

 Icon., vol. 19, Cumingia, pi. 1, fig. 3 Chile, Peru. 



Subtrigonal, white, nearly equilateral, if normal, the umbones high, 

 median, with pointed, slightly prosogyrate beaks. Anterior side widely 

 rounded, fairly convex along the umbonal slope, the posterior end obtusely 

 rounded. Sculpture formed by fine, threadlike concentrics between wider 

 interspaces, the surface of which is minutely radially striate. A large speci- 

 men measures: Length 19.8 mm., height 16 mm., semidiameter 5.1 mm. 



A thinner, usually less distorted and more finely sculptured species 

 than C. lamellosa. Specimens from northern Peru are much smaller than 

 from further south. 



Range — Ecuador to Chile. Peru: Paita; Callao. 



Cumingia adamsl Carpenter Plate 67, figures 6, 6a 



Cumingia — .sp. indet. c. C. B. Adams, 18S2, Ann. Lyceum Nat. Hist. New York, vol. 



5, p. 512, No. 483. 1 valve, Panama. 

 Cumingia adamsi Carpenter, 1863, Proc. Zool. Soc. London, p. 367. — Carpenter, 1872, 



reprint. Smith. Misc. Coll., No. 252, B. p. 203, No. 483. 



483. Cumingia sp. ind. c. M. 45. This appears a distinct species and 

 may be quoted as C. adamsi, in remembrance of the labours of Messers. 

 H. A. and C. B. Adams. (Carpenter, 1863.) 



The original specimen has never been figured or adequately described 

 but through the kindness of William J. Clench of the Museum of Compar- 

 ative Zoology, Harvard, I have been able to examine and photograph the 

 type, a picture of which is given here. 



Shell small or of medium size, thin, white, obliquely trigonal-ovate, 

 convex, with small, nearly median, erect beaks. Anterior side impressed 

 below the beaks and with a nearly circular marginal outline; the posterior- 

 dorsal margin descending to form a narrowly rounded or blunt posterior 

 end. Surface marked with fine, rather widely and evenly spaced, concentric 

 lamellar lines, the space between each pair ornamented with fine radial 

 striae which on the anterior-umbonal slope divaricate or fan out rather sharp- 

 ly towards the margin; on weathering, the surface appears almost smooth. 

 Pallial sinus large and deep, its upper limb not reaching to the anterior 

 adductor scar, coalescent with the pallial line below. Hinge normal, the 

 lateral teeth small. 



Length 9.6 mm., height 8.1 mm., thickness of one valve, 2.2 mm. Holo- 

 type, a left valve MCZ 203763. Panama. 



Length 16.6 mm., height 12.7 mm., thickness of one valve 4.2 mm. 

 Jaramijo, Ecuador, mud flats. 



The type is slightly worn so that its surface appears nearly smooth, 

 but the fine radial striae are visible along the anterior-umbonal slope. The 

 species is distinguished by its regular, undeformed shell, and characteristic 

 sculpture. 



