. West coast shells. A familiar description of the marine, fresh water, and land mollusks of United States, found west of the Rocky Mountains ... Fig. 147. within, and covered with a greenish brown epider-mis; almost transparent at the umbones. The hinge-line is prolonged obliquely upward, forming a nearlyright triangle above the oval part of the shell. Itslength is three inches. The specimen for theengraving was taken from the San Joaquin river. ANODONTA 175 Anodonta Oregonensis, Lea, Or-e-gon-en-sis, has*a shell oval in outline, rather thin, pearl-tinted, andcovered with a dark or greenish e
. West coast shells. A familiar description of the marine, fresh water, and land mollusks of United States, found west of the Rocky Mountains ... Fig. 147. within, and covered with a greenish brown epider-mis; almost transparent at the umbones. The hinge-line is prolonged obliquely upward, forming a nearlyright triangle above the oval part of the shell. Itslength is three inches. The specimen for theengraving was taken from the San Joaquin river. ANODONTA 175 Anodonta Oregonensis, Lea, Or-e-gon-en-sis, has*a shell oval in outline, rather thin, pearl-tinted, andcovered with a dark or greenish epidermis. Theoldest parts of the shell, which in this case are at theumbones, are often partially dissolved by the acids inthe river-water, leaving the white shell are no hinge-teeth. The hinge-line is nearlyparallel to the base of the shell, quite different fromthe last species. The specimens described weregathered in the north, from the Columbia river, nearThe Dalles, and in the south, from the vicinity ofLos Fig. 148. Anodonta NuttalUana, Lea, is very similar to Cali-forniensis, as is also A. Wahlamatensis, Lea. I con-sider them both as only varieties of that species. Anodonta angulata, Lea, an-gu-la-ta, Fig. 148,however, is distinct and has a well-marked form. Itis much wider at one end than at the other, and ismarked by a sharp angle running obliquely from theumbo to the corner of the shell. Epidermis dark 176 RIVER PEARL-SHELLS. brown; shell pearly within, somewhat length is three inches, which is twice the height. Margaritana margaritifera, Iyinn., Mar-gar-i-ta-namar-gar-i-tif-e-ra. This fresh-water mnssel is widelydistributed, being found in the eastern part of theUnited States, and also in Europe. The shape of itsshell is oblong, somewhat bulged at the and solid; hinge-teeth strong, triangular. Epi-dermis dark, internal color somewhat purple, lengththree inches. Found in the Chehalis river of Wash-ington, and the S
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectmollusks, bookyear188
