CLASS GASTROPODA 
305 
absent. Length, 23; breadth, 13j4 mm.; divergence, 105-115°. The in¬ 
terior is a deep blue-green, or gray-blue with a purple-pink blush. (Tryon 
and Pilsbry, Manual of Conchology .) 
Type in Philadelphia Academy of Natural Sciences. Type locality, 
Bolinas Bay, California. 
Range. Known only from the type locality. 
Mopalia muscosa laevior Pilsbry, 1918 
Nautilus, 31:126. Tryon and Pilsbry, Manual of Conchology, 14:300; PL 63, figs. 60-61. 
This name has long been used in the collection for the form figured 
and described in Manual of Conchology, Vol. 14, p. 300, pi. 63, figs. 60-61. 
(Pilsbry, Nautilus.) 
One of the principal mutations of Mopalia muscosa is toward still 
smoother forms entirely lacking pitted or reticulated sculpture, having only 
a few subobsolete longitudinal wrinkles on the ridge, the pointing in 
concentric streaks (following growth marks) on each valve. (Tryon and 
Pilsbry, Manual of Conchology.) 
Type in Philadelphia Academy of Natural Sciences. Type locality, 
Olympia, Washington. 
Range. Known only from the type locality. 
Mopalia muscosa lignosa Gould, 1846 
Proceedings of the Boston Society of Natural History, 2:142. Tryon and Pilsbry, 
Manual of Conchology, 14:299; PI. 63, figs. 58-59. 
Testa solidula, ovata, tectiformis, caesia, lineolis fuscis inaequalibus 
subradiantibus marmorata, systemate duplici punctorum majorum et punc- 
torum minorum impressa; valvis planulatis, angulatis, sine rostris; areis 
lateralibus haud elevatis, vix distinctis; valva anteriori parva; valva pos¬ 
teriori vix umbonata: intus aeruginosa. Long., Ij4 ; lat., % poll. (Gould.) 
Shell oval, elevated, carinated or angular at the dorsal ridge, the side- 
slopes straight. Surface lusterless, apparently smooth; grayish, greenish, 
or bluish with radiating streaks, lines and flammules of brown or purple- 
brown. Under a lens the lateral areas appear nearly smooth; the central 
areas being closely and finely pitted all over. Girdle narrow, sparsely hairy. 
Interior white and light blue. Length, 60; breadth, 35 mm.; divergence, 
120°. (Tryon and Pilsbry, Manual of Conchology.) 
Type in ? Type locality, Puget Sound. 
Range. Sitka, Alaska, to Magdalena Bay, Lower California. 
[907] 
