46 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



Body rings, 1 + 10. Caudal rings, 37. Tubercles of body and tail 

 elongated, slightly recurved, usually prolonged into slender filaments ; 

 those on the 2d, 4th, and Gth body rings much larger than the others; 

 tubercles prominent and filamentose upon the 4th, Gth, 9th, 12th, 16th, 

 and 20th caudal rings. Ventral tubercles upon Gth, 7th, 8th, and 9th 

 body rings. Occipital crest very high, with five prominent tubercles, 

 the anterior two with long filaments. Length of snout equal to dis- 

 tance from posterior margin of orbit to gill-opening. Operculum marked 

 with fine, radiating striae. 



Radial formula.— D. 19 (the first imperfect). P. 18. V. 4. 



Color. — Yellowish-brown; the eyes and cheeks covered with radiating, 

 wavy lines of light brown. Snout encircled by a narrow, undulating, 

 white band near its middle. 



The Commission has an accurate sketch by Mr. Eraerton. 



April 30/1878. 



DESCRIPTIONS OF IV E W SPECIES OE SHELLS B HO U CALIFORNIA 

 I IV THE COLLECTIONS OF THE NATIONAL MUSEUM. 



By W. H. DALL, 



Haliotis (?var.) assimilis, n. s. 



Shell solid, strong, not very thick, with a rather light pink, white and 

 greenish nacre, usually with five open holes ; spire more elevated than 

 that of any other Californian species, consisting of two and a half or 

 three whorls ; aperture very oblique in adult specimens, the thickened 

 margin of the columella narrow, somewhat concave, inclined sharply 

 inward and upward, about three-fourths as long as the columellar side, 

 of the aperture. Between the row of openings and the columellar edge, 

 the space is unusually broad, marked midway by an obtuse carina, sep- 

 arated from the row of holes by a shallow channel : surface reddish or 

 dull greenish, with rather rough, crowded, unequal, spiral ribs and 

 rounded, irregular, wavy, radiating undulations crossing the spiral 

 sculpture obliquely. The muscular impression, in most specimens, is 

 but lightly marked, and, except for occasional spot-like impressions, is 

 smoothly nacreous, like the rest of the interior. Lon. 4.5 in. Lat. 3.0 

 in. Alt. of spire 1.5 to 2.0 in. Aperture 3 inches wide and 3.75 long, 

 in au adult specimen. 



Habitat. — Monterey; Sau Diego, Cal.; in deep water only; thrown 

 up by heavy storms, usually dead and worn when found and everywhere 

 rare. Mas. Cat. 31267. 



This species, or variety, has long been known to me and to most 

 Californian collections, but has not hitherto been characterized, owing 

 to the dead condition of most of the specimens found. Mr. Hemphill 

 having forwarded two fresh specimens, it seems well to put it on record. 



The form is different from any other Californian species; the spiral 



