76 IS. IIN'H'HITON. 



2Y< ' u., Rep. Brit. Asso. Adv. Sci. 1863, p. 



Inchnochiton (Trachydermoii) Jiectens Cri:., 1*100. Acad. >'at. 

 Sci. Phila. 1865, p. 60. 



A variety i'rom Catalina Is. has the posterior valve with 7, inter- 

 mediate 1 . anterior 8 slits, the mucro less anterior ; divergence 90. 

 (Opr.) 



I. LIVIDUI Middendorff. PI. 6, figs. 22, 23, 24. 



Shell elevated, teL'inentum smooth, shining, livid. Anterior 

 valve, lateral areas and posterior valve obsoletely radiately ril>- 

 stiiate. Central areas longitudinally costulate, the riblets sepa- 

 rated, .-harply cut, whitish, 18-20 in number. Lateral areas 

 depressed. (Jills median. 



Length 23 mill.; divergence 120. 



Sitka. 



Chiton (Stenosemus) lividus MIDD., Beitr. zu einer Malac. Ros- 

 sica, i, p. 124, t. 13, f. 3, 4. 



This species and the next have not been found by later observers. 



I. SCROBICULATUS Middendorff. PI. 8, figs. 66, 67, 68. 



Shell depressed, tegmentum rough, opaque, ashen or yellow- 

 brown. Central areas regularly pitted in longitudinal series; lat- 

 eral areas swollen, divided by a radiating groove which widens 

 below. Girdle having narrow scales. Gills median, 16 in number. 



Length 9 mill.; divergence about 130. 



California, 



Chiton (Stenosemus) scrobicnlatus MIDD., Mai. Ross, i, p. 127, t. 

 14. i 1 . 4-7. 



I. SOLIDIOR Carpenter, n. sp. Unfigured. 



Shell small, oval, somewhat elevated, rather flesh-colored; jiifrum 

 obtuse ; niuero elevated, in front of the middle. Valves pointed, a 

 little rounded at the margins; lateral areas scarcely defined. 

 Entire surface smooth, under a lens minutely roughened and very 

 minutely punctate ; wrinkles of growth conspicuous. 



hind.-: posterior yalye with 9, anterior with - s , median with 1 

 slit; the teeth obtuse, solid, much separated, at times somewhat 

 roughened. Sinus wide, flat ; caves *h<>rt. 



(iirdle normal I'm- TrnrJiiidr,-nin, the granules solid. 



