Vol. IX] BERRY— NOTES ON WEST AMERICAN CHITONS / 



granules less regular than those just described, those of the 

 central areas showing a tendency to overlap or coalesce so as 

 to form distinct longitudinal riblets. Posterior valve with 

 similar sculpture ; semicircular ; mucro conspicuous, much 

 elevated, projected posteriorly, and almost overhanging; 

 posterior slope steep and strongly concave. Margins of 

 tegmentum everywhere finely crenulate. 



Interior of valves grayish white, translucent, minutely pit- 

 ted ; median valves thickened at the middle ; posterior valve 

 with a conspicuous V-shaped, laterally branching callus. 

 Sinus broad. Sutural laminae triangular. 



Girdle narrow, for the most part with a pilose covering of 

 excessively minute, short, pointed spinelets, among which are 

 interspersed sundry long, conspicuous, stiletto-like, or more 

 often curved spines, appearing especially numerous in the 

 neighborhood of the sutures. Marginal spines minute. 



Ctenidia 12-16 on a side, extending past the middle of the 

 6th valve. 



Radula with strongly bidentate major laterals. 



Color of dorsal surface a warm yellowish brown, very 

 finely and copiously, though variously, mottled with longi- 

 tudinal and radial streaks of a dark slaty gray. Girdle with 

 dorsal mottlings or almost unicolored. 



Measurements: Long. 13.1, diam. 7.0 mm. 



Type: An alcoholic specimen [S. S. B. 123], comprising 

 Cat. No. 3513 of the author's collection. Paratypes deposited 

 in the collections of the California Academy of Sciences, the 

 Academy of Natural Sciences of Philadelphia, the United 

 States National Museum, and the Department of Zoology of 

 Stanford University. 



Type Locality: 15 fathoms, off Monterey, California; H. 

 Heath, summer, 1908; 12 specimens. 



Remarks: I have had this species in hand for a number of 

 years without hitherto being able to attach a satisfactory name 

 to it. It is a well marked and not at all a rare form, chiefly 

 characterized by its peculiar coloration and a girdle armature 

 quite unlike that of any of the better known West American 

 species of the genus. For a time I was (very doubtfull)'') 

 inclined to identify the species with the insufficiently under- 

 stood L. nexus Carpenter 1864, but Carpenter's description 



