NO. 2283. NEW PACIFIC COAST CHITONS— D ALL. 611 



appear to join each other in front of the obsolete jugal sinus. Length, 

 10; width, 6, height, 2 mm. 

 11 ahitat— Shore at San Pedro, California. Cat. No. 218770, 



U.S.N.M. 



CALLISTOCHITON AEPYNOTUS, new species. 



Chiton 3'^ellowish white, with a keeled back, the girdle as usual in 

 the group ; anterior valve with 10 annulate ribs and a slit for each rib ; 

 posterior valve small, low, with only about 5 feeble ribs, and 5 

 slits, the central area reticulate; intermediate valves with a narrow 

 smooth line at the jugum, and single slits; the pleural tracts sharply 

 obliquely reticulate with deep interspaces; the lateral areas bounded 

 by 2 strong annulate ribs, the posterior rib wider, the interspaces 

 regularly punctate-reticulate; interior white, the jugal sinus almost 

 obsolete. Length, 15 ; width, 7 ; height, 5 mm. 



Hahitat. — Puget sound, in 37 fathoms rocky bottom, temperature 

 46°. United States Fish Commission. Cat. No. 225448, U.S.N.M. 



One of the specimens has the distal nodule of a black color on each 

 rib, all round the border. 



CALLISTOCHITON CYANOSUS, new species. 



Chiton of moderate size, rounded back, and rather low dorsum, the 

 color pale blue with interrupted bands of straw-color, the girdle 

 armature as usual, but rather finer and pale in color; anterior valve 

 with 11 keeled ribs, a slit to 9 of them; these ribs are crossed by fine 

 concentric threads with about equal, not punctate, interspaces; pos- 

 terior valve low, with subcentral inucro similarly sculptured, the cen- 

 tral area rather larger than the ribbed portion with 10 or 11 promi- 

 nent axial threads on each side, the interspaces crossed by similar 

 threads, making a conspicuous reticulation ; in the posterior portion 

 are 8 carinate ribs each with a slit; the intermediate valves with 

 one slit on each end, the lateral areas bounded by 2 strong keeled 

 ribs crossed by small equal threads, not punctate in the interspaces, 

 denticulating the posterior edge of the area; jugal areas showing a 

 narrow triangular smooth space, on each side of which are 15 or more 

 strong straight axial threads, the subequal interspaces reticulated by 

 smaller threads and the interstices deep ; interior bluish white with 

 a wide straight-edged jugal sinus and rather broad sutural laminae. 

 Length, 13 ; width, 8 ; height, 3 mm. 



Hahitat. — Long Beach, San Pedro, California, Mrs. Hartwell. Cat. 

 No. 109317, U.S.N.M. 



This has somewhat the characters of Ischnochiton, toward which it 

 makes a partial approach. 



CALLISTOCHITON CHTHONIUS. new species. 



Chiton of moderate size and dark reddish brown color, including 

 the girdle which exhibits small lozenge-shaped imbricating scales 



