NTJTTALLINA. 279 



The white spines are often striated when young, as are the scale- 

 like spines of Middendorffia. 



N. CALIFORNIA Nuttall. PL 54, figs. 23, 24 ; pi. 56, fig. 12, 13, 



14, 15, 16, 17, 18. 



Shell elongated, more than twice as long as wide, moderately 

 elevated, carinated or somewhat rounded. Surface finely corrugated- 

 granular, lusterless ; color dark brown, dark olive-brown or black- 

 ish, unicolored or having one or three whitish stripes along the 

 summit of the second valve. 



Median valves strongly beaked, v-shaped, the anterior margin of 

 the tegmentum trilobed; having a smooth shining rounded dorsal 

 ridge (sometimes obsolete and often eroded), bounded by a pair of 

 diverging, shalloiv furrows ; the entire sides of the valves (pleura and 

 lateral areas') closely granulated, the granules irregularly arranged 

 in rows. Lateral areas not raised but indicated by a low curved 

 diagonal rib, behind which and parallel to it, there is a shallow 

 sulcus. Anterior valve having 11 low rounded radiating ribs, the 

 entire surface granulated. Posterior valve depressed, small, the 

 mucro posterior and terminal, projecting beyond the posterior margin 

 of the eaves. 



Interior bluish, sometimes stained with blackish at jugum and 

 bases of the sutural plates. Sutural plates very long, separated by a 

 wide, deep, square sinus; behind which is a punctate and laminate 

 area. Anterior valve having 11 or 10, median valves with two slits, 

 or at least two punctulate slit-rays, the posterior slit being usually 

 indistinct or wanting from the more or less complete obsolescence of 

 the posterior tooth ; te"eth sharp, smooth, long, not thickened at the 

 edges of the slits. Posterior valve having 8-9 slits, the teeth chisel- 

 shaped, sharp, smooth, very strongly directed forward. Eaves nar- 

 row, spongy. 



Girdle closely covered with short, rigid calcareo-corneous spine- 

 lets, mostly of a scorched brown color with a few white spines inter- 

 mingled (pi. 54, fig. 24.) 



Length 37, breadth 15 mill. (Large specimen from Monterey.) 



Length 26, breadth 13J mill. (Specimen collected by Nuttall.) 



Vancouver Island south to Piedras Blancas, near S. Simeon, San 

 Luis Obispo Co., California. 



Chiton californicus NUTTALL in Brit. Mus. and Mus. Phila. 

 Acad. KEEVE, Conch. Icon., pi. xvi, fig. 89 (March, 1847). Nut- 



