214 Kansas Academy of Science. 



45. Mactra (Spisula) falcata?. Plate V, figs. 45, a, h, c. 



This species resembles M. falcata, except it is more oval in out- 

 line; inside of shell not seen. It also resembles M. Oibbsana but 

 is less gibbous and has less prominent umbones. 



Found with the other Madras in the Quillayute formation at 

 the old mouth of Maxfield creek. 



Superfamily Myacea; Family XXXVI Myacid-s:; Genus Mya. 



Shell solid, large, irregular, gaping behind; hinge edentulous; 

 surface smooth. 



46. Mya truncata Linne. Plate V, fig 46; times, one-half. 



Mya truncata Linn. Crag. Moll., vol. II, p. 277, tab. XXVIII, fig. 1. 

 Sears V. Wood, supplement to the Mont. Crag. Moll. Pal. Soc, vol. 27, 

 p. 136. Billings, Geol. Can. 1863, p. 963, fig. 474. Arnold, U. S. G. S. 

 Bull, 309, pi. 18, fig. 1. 



Posterior extremity of shell (cast) broken. Shell large, rather 

 thin; valves unequal, elongated, rounded in front and gaping be- 

 hind, with a sinus trough-like area back of front margin, the one 

 in the right valve being wider and deeper than the one in the left 

 valve; umbones of medium size, placed anteriorly and pointed for- 

 ward; surface smooth except for very fine incremental lines of 

 growth. 



Dimensions: Alt., 61. 



A single specimen was obtained from the Quillayute formation. 



Recent fauna: Arctic regions (Arnold). 



Pleistocene, etc.: This species is found in England, in the Red 

 Crag of Butley; in the Scrobicularia bed; in the Fluvio-Crag, at 

 Bramerton; in the Ohillesford bed, at Chillesford; at Sudborn 

 Church Walks; in the glacially, pebbly sands at Kunten Gap, and 

 in the middle glacial sands at Hopton, and at Bridlington ( Wood ) . 



Post-Tertiary of Canada (Logan; Billings). 



Pliocene: California (Logan; Billings) ; Fernando formation of 

 Elsmere Caiion, near Newhall. Los Angeles county, California 

 (Arnold) ; Qaillayute, Wash. ( Reagan) . 



Class VII Gasteropoda; Order Opisthobranchiata. 

 Family XLIII Scaphandrid^e; Genus Cylichna Loven. 



"SHell strong, cylindrical, smooth or punctate-strise; spire mi- 

 nute or truncated; aperture narrow, rounded in front; columella 

 callous, with one plait. Cylichna arachis Quoy.is a characteristic 

 species." (Arnold.) 



47. Cylichna alba Brown. Plate V, fig. 47. 



Cylichna cylindracea (non-Linne), Cpr., Brit. Assn. Rept., 1863, p. 647; 

 Cooper 7th Ann. Rept. Cal. St. Min.. 1888, p. 238. 



