98 PALAEONTOLOGY OF CALIFORNIA. 



HAYDENIA, N. Gen. 



SHELL massive, allied, in general form, to Oliva, spire low. 

 Outer lip simple, not thickened nor crenulate; inner lip incrusted, 

 callus most marked posteriorly, without teeth or folds; canal 

 slightly recurved; anterior extremity of the mouth notched, and 

 a small sinus at the posterior extremity of the aperture, where 

 the outer lip unites with the body whorl. Surface ornamented 

 as in some of the Buccinidse. 



This curious form is probably a link between Buccinum and the genus Volut- 

 harpa, Fischer. It differs from the latter in the thick shell, the presence of the 

 posterior sinus, the strongly recurved canal, and the sculpturing of the surface. 

 The irregular, rough surface at once separates it from Oliva; since, in the present 

 form, the mantle of the animal, evidently, never enveloped the shell. 



Named in honor of Dr. F. V. Hayden, of "Washington. 



H. IMPRESSA, n. 8. 







PI. 18, Fig. 51. 



SHORT, robust, shell thick, spire low; whorls four, almost en 

 tirely enveloped; body whorl expanded. Aperture broad, colu- 

 mella curved, coated by a callus varying in size slightly, in 

 different individuals, extending posteriorly above the suture. 

 Canal slightly recurved; anterior sinus broad, posterior sinus 

 small, as deep as wide, rounded. Surface marked by a groove 

 parallel with the suture and immediately below the sinus and 

 on the anterior half of the shell, by seven or eight distinct, im 

 pressed, revolving lines, These are crossed by numerous strong, 

 irregular lines of growth 



Figure, natural size. 



Localities: Tuscan Springs, Tehama County (Division A.), collected by Dr. 

 Veatch ("Lick Springs" of Dr. Veatch); and Pence's Kanch, Butte County. 



