NO. 2283. NEW PACIFIC COAST CHITONS— BALL. 507 



anterior valve with 9, posterior with 8, intermediate valves with 1 

 slit at each end ; the anterior valve is less than semicircular and is ob- 

 scurely granulose; the surface of all the valves is polished; posterior 

 valve is small, with low subcentral mucro, the central area axially 

 grooved, the posterior area with low granules interspersed with punc- 

 tations; intermediate valves with the jugal area nearly smooth or 

 with faint punctations, but not definitely differentiated from the 

 pleural tracts, which are sharply grooved in a generally axial but 

 more or less vermicular manner; the lateral areas are denticulate on 

 their posterior edges and irregularly divaricately strongly ridged; 

 the armature of the girdle is composed of minute densely imbricated 

 scales; the gill rows are ambient; the jugal sinus shallow, with a 

 straight edge, the sutural laminae subrectangular. wide apart. 

 Leng-th of shell, 8 ; width, 4.5 ; height, 3 mm. 



Babitaf.—GwU of California, W. J. Fisher. Cat. No. 58865, 

 U.S.N.M. 



This is another of Dr. Paul Bartsch's manuscript species. 



ISCHNOCHITON BERRYI, new species. 



Chiton of moderate size, deep crimson with irregular blotches of 

 brown and white on its lateral slopes, and a crimson girdle of 

 rounded densely imbricated small scales ; gill rows ambient ; anterior 

 valve with a nearly smooth mucro, from which radiate about 20 

 more or less corrugated, sometimes bifurcating threads, the whole 

 overspread like the rest of the shell by an almost microscopic decus- 

 sation; anterior slits about 12; posterior valve much smaller with a 

 subcentral mucro, from which radiate threads, lilte those on the an- 

 terior valve, in all directions; posterior slits 11; intermediate valves 

 with one slit, jugal area minutely decussated, almost carinate; lateral 

 areas with usually three corrugated ribs, the nodulation of the pos- 

 terior rib undulating the margin of the valve, but there may be one 

 or two minor intercalary ribs; the pleural areas are axiall}^ ribbed 

 with deep decussated interspaces, the ribs growing stronger as they 

 recede from the jugal region; interior pink, the jugal sinus hardly 

 marked, axially striated, merging laterally into narrow sutural lami- 

 na3. Length of shell, 11; width, 7; height, 2.5 mm. 



Habitat. — Pacific Grove, Monterey Bay, California. Cat. No. 

 193375. U.S.N.M. 



This is one of Dr. Paul Bartsch's undescribed species. 



ISCHNOCHITON (STENOPLAX) AETHONUS, new species. 



Chiton narrow and elongate, of deep rose pink, Avith or without 

 whitish mottling along the dorsal ridge, which is evenly rounded; 

 girdle brownish, covered with a dense coating of short, even, minute 

 spinules of a grayish-white color, giving a smooth arenaceous sur- 

 face; anterior valve more than semicircular, sculptured with equal, 



