NO. 2283. NEW PACIFIC COAST CHITONS— BALL. 501 



the jugal sinus wide with a straight edge, the sutural laminae small, 

 subtriangular. Length of dry animal, 5; Avidth 2; height, 0.7 mm. 



Ilabif at. —Monterey, California. Cat. No. 218TG7, U.S.N.M. 



This species was discriminated by Dr. Paul Bartsch some years 

 ago, but not published. 



LEPIDOPLEURUS (LEPTOCHITON) AGESILAUS, new species. 



Chiton small, with a rounded back and verj narrow girdle, the 

 valves white, but coated with a black deposit (manganese ?) which 

 obscures the sculpture; anterior valve nearly semicircular, with al- 

 most microscopic radial striation decussated by concentric even finer 

 striae; posterior valve with a moderately prominent mucro slightly 

 in front of the center, the central area finely axially puncto-striate, 

 the posterior area radiatelv striate, the ridges more or less granuloso 

 from intersection by concentric striation; intermediate valves with 

 obscure concentrical undulations which make the posterior edge 

 irregularly denticulate; pleural tracts and undifferentiated jugal 

 area axially minutely puncto-striate; girdle minutely densely spinose, 

 the ends of the spinulae forming an arenaceous even surface except at 

 the outer margin which has a short fringe of slightly longer whitish 

 spinules; interior whitish, the jugal sinus obsolete, the sutural laminae 

 small, narrow. Length of animal, 8; width, 5; height, 3 mm. Gills 

 ambient. 



Hahitat. — Straits of Magellan in Gl fathoms sand, bottom tempera- 

 ture 48° Fahrenheit. United States Fish Commission steamer 

 Albatross. Cat. No. 96227, U.S.N.M. 



One of the specimens has only half the seventh valve developed, 

 the vacant space being covered by a widening of the sixth valve on 

 that side. 



LEPIDOPLEURUS (LEPTOCmTON) NICOMEDES, new species. 



Chiton of moderate size, yellowish white, with a moderately wide 

 girdle covered with an even pavement-like series of nearly rectangu- 

 lar subequal ivory-white smooth scales set in radial lines; back 

 almost keeled, the mucrones of the intermediate valves prominent 

 and whiter than the rest of the surface ; anterior valve semicircular 

 with faint granular minute radial threads, and a general sculpture 

 of very minute reticulation; posterior valve with a small mucro at 

 the anterior third, the central area narrow and faintly concentrically 

 sculptured; the posterior area somewhat concave, sculptured like 

 the anterior valve; intermediate valves without distinct jugal area, 

 that and the pleural tracts sculptured only with a microscopic 

 decussation; lateral areas conspicuous, with about three radial low 

 coarsely granular ribs; interior whitish; jugal sinus inconspicuous, 

 the sutural laminae long, narrow. Length of shell, 10; width, 6.5; 

 height, 4 mm. Gill rows about two-thirds as long as the foot. 



