CHITONS TAKEN BY THE UNITED STATES FISHERIES STEAMER "ALBATROSS" IN THE NORTHWEST PACIFIC IN 1906. By S. Stillman Berry, Scripps Institution fur Biological Research, La Jolla, California. A small series of chitons taken in the course of the Northwest Pacific Expedition of the United States Fisheries Steamer Albatross during the summer of 1906 was kindly transferred to the writer by Dr. Harold Heath, of Stanford University, for study and report, and forms the subject matter of the present paper. Though rich neither in species nor in individuals, the fact that our knowledge of the chiton fauna of this region is slight and the fortunate circumstance that the specimens were kept in alcohol render the material noteworthy. The collection comprises in aUsome 45 specimens. These are referable to 11 species, of which the 4 named below are described as new: Leptochiton diomedeae, new species. Ischnocliiton (Lepidozona) amahilis, new species. IschnocTiiton {Lejndozona) interfossa, new species. Ischnocliiton (Lepidozona) pilshryanus, new species. Family LEPIDOPLEURIDAE. Genus LEPTOCHITON Gray 1847. LEPTOCHITON DIOMEDEAE, new species. Plate 1, figs. 1-3; plate 2. Description. — Shell rather small, elliptical, the shell and girdle together approximately twice as long as broad. Insertion plates lacking. Valves moderately elevated, sharply arcuate. Anterior valve with a concave anterior slope due to the apical region rising more abruptly than the slightly flaring marginal region; posterior margin broadly /\ -shaped in outline when the valve lies in its normal position. Median valves with small but sharp and rather prominent beaks, their anterior margins only slightly arcuate except the second Proceedings U. S. National Museum, Vol. 54— No. 2223. 3343— 19— Proc.N.M.vol.54 2 1
BioStor
