CLASS GASTROPODA 
247 
striated scales. Length, S l / 2 ; breadth, 2 y 2 mm. (Tryon and Pilsbry, Man¬ 
ual of Conchology.) 
Type in British Museum. Type locality ? 
Range. Bering Strait to Sitka and Oregon, North Atlantic, Green¬ 
land. 
SECTION LEPTOCHITON Gray, 1847 
Lepidopleurus rugatus (Carpenter) Pilsbry, 1892 
Tryon and Pilsbry, Manual of Conchology, 14:11; PI. 3, figs. 67-70. 
Oval, rather convex, the lateral slopes nearly straight, dorsal ridge 
broadly arched. Front and back valves and lateral areas of the inter¬ 
mediate valves sculptured with excessively fine radiating striae, which 
are feebly granose, and having well-marked, coarse, concentric wrinkles; 
central areas having an equally minute sculpture of longitudinal subgra- 
nose striae. Mucro subcentral and prominent. The lateral areas are slightly 
raised. Length, 13-14; breadth, 7 mm. (Tryon and Pilsbry, Manual of 
Conchology .) 
Type in Philadelphia Academy of Natural Sciences, No. 35586. Type 
locality, San Tomas River, Lower California. 
Range. Monterey, California, to Todos Santos Bay, Lower California. 
This is Carpenter’s MS L. internexus var. rugatus. 
Lepidopleurus internexus Carpenter, 1892 
Tryon and Pilsbry, Manual of Conchology, 12. 
Shell similar to L. nexus, but much smaller, orange-colored. Valves 
regularly arcuate, without jugum. Sutural plates small, triangular; sinus 
larger. Girdle with more solid scales, scarcely pilose. Length, 4 y 2 ; 
breadth, 3*4 mm. (Carpenter.) (Tryon and Pilsbry, Manual of Con¬ 
chology.) 
Type in ? Type locality, Santa Barbara, California. 
Range. BelkofiFski, Alaska, to San Diego, California. 
Lepidopleurus ambustus Dali, 1919 
Proceedings of the United States National Museum, 55:499. 
Chiton with a rather high but rounded back, the valves reddish-brown 
with numerous blackish flecks, giving the interspaces a somewhat vermicu¬ 
lar aspect; anterior valve semicircular, simple; posterior valve smaller, 
shorter, with a subcentral prominent mucro, behind which the surface is 
concavely excavated; intermediate valves subequal, dorsally rounded with 
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