LEPIDOPLEURUS. 11 



L. CONCINNUS Gould. Unfigured. 



Shell minute, reddish, elliptical, vaulted, all over punctate [granu- 

 lose], the points arranged in radiating, curving series ; lateral areas 

 hardly elevated, longitudinally waved. Front valve crescentic ; 

 posterior valve with an acute umbo. concentrically waved. Girdle 

 narrow, buff. (Gld.} Length 8, breadth 5 mill. 



Sutural plates small, subtriangular ; jugal sinus very wide, flat ; 

 scales of the girdle delicate. (Cpr.} 



Hakodadi, Japan, laminarian zone, on shells and stones. 



C. (Leptochiton) concinnus GLD., Otia Conch, p. 117. Lepto- 

 chiton concinnus CPU. MS., p. 3. DALL, Proc. U. S. Nat. Mus. p. 

 318, 316, 1878. 



L. NEXUS Carpenter. Unfigured. 



Shell small, whitish-ashen, valves gothic-arched ; lateral areas 

 scarcely denned ; entire surface ornamented with series of subquad- 

 rate granules, the series longitudinal upon the central, radiating 

 upon the lateral areas and end valves, very close, scarcely inter- 

 rupted. Jugum elevated, subacute; umbones inconspicuous. Mucro 

 conspicuous, median. Inside with strong sutural lobes and a wide 

 plane sinus to the middle valves ; insertion plates obsolete. Girdle 

 having narrow, close, striated scales and needle-shaped, crystalline 

 bristles here and there and around the margin. (Qor.) 



Length 7, breadth 4| mill.; div. 90. 



Calalina Island, California, 20-80 fins. 



Leptochiton nexus CPU., Hep. Brit. Asso. Adv. Sci. for 1863, p. 

 650,1864; Proc. Cal. Acad. iii, p. 212, 1866; ma. p. 2. DALL, 

 Proc. U. S. Nat. Mus. 1878, p. 316, 319. 



A variety is prettily variegated with olive, has stronger sculpt- 

 ure, and the valves slightly beaked. The spicules which appear on 

 the girdle among the striated, elongated scales, are very numerous. 

 It is curiously like the young of Ischnochiton radians. ( Cpr.} 



See notes under L. cancellatus for comparison with that species. 



L. RUGATUS Carpenter, n. sp. 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 intermediate valves sculptured with excessively fine radiating 

 striae which are feebly granose, and having well-marked, coarse, con- 

 centric wrinkles; central areas having an equally minute sculpture 



