301 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



Mopalia ciliata. 



Chwtoplcnra miiscosa Gonld, Otia, p. 242, 18G2. 



Mopalia muscosa Carpenter, Suppl. Rep. IJr. As. 1883, p. 648. 



Chiton WossnessensMi Midd. Mai. Ross, i, p. 101, 1847 ; in part only; figure and 



part of diagnosis excl. 

 Chiton armahis (Nutt. ) Jay, Cat. 1839, No. 2678. No dcscr. 

 Chiton ornatus Nuttall, MS. Brit. Mus. Col. etc. and 

 Chiton consimili^ Nuttall, MS. loc. cit. never described. 



Suhsp. Mopalia lignosa. 



Chiton lif/nosits Gould, Proc. Boston Soc. Nat. Hist, ii, ii. 142, July, 1846 ; Otia, p. 



3, 1882 ; Exp. Sli. p. 330, f. 424, 1852. 

 Chwto2)let(ra lignosa Gould, Otia, p. 248, 1862. 

 Mopalia lignosa Carpenter, Suppl. Rep. Br. As. 1863, p. 648. 

 Chiton Merckii Midd. Bull. Imp. Acad. Sci. St. Petersb. t. vi, p. 20, 1846 ; Mai. 



Ross, i, p. 115, pi. xi, f. 5-6, 1847. 

 Chiton EschsclioUzii Midd. Bull. 1. c. p. 118 ; Mai. Ross. 1. c. p. 114, pi. xi, f. 4 (t. 



jun.). 

 Chiton {Hamachiton, Stenosemus) Merckii Midd. 1. c. p. 34. 

 Chiton Montereyensis Cpr. P. Z. S. 1855, p. 231. 



Chiton vcspertinus Gould, Moll. U. S. Expl. Exp. p. 323, f. 426, 426 a, 1852. 

 Chwtoplcnra vesperiina Gould, Otia, pp. 230, 242, 1862. 

 Mopalia vcspertina H. «fc A. Adams, Gen. Rec. Moll, i, p. 479, 1854. 

 Mopalia Simpsoni Gray, P. Z. S. 1847, p. 69. — H. & A. Adams, Gen. Rec. Moll, i, p. 



479, 1854; Brit. Mus, Coll. In all cases name only; never described. 



(From type.) 

 Chiton calif ornicns (Nutt. MS.) Reeve, Couch. Ic. Mon. Cbiton, pi. xvi, f. 89, 1847. 



far. M. Hindsii. 



Chiton Uindsii (Sowerby MS.) Reeve, Concli. Icon. Mon. Cliitou, pi. xii, f. 67, a, 



h, 1847. 

 Mopalia Hindsii Gray, P. Z. S. 1847, pp. 69, 169.— H. & A. Adams, Gen. Rec. Moll. 



i, p. 478, pi. liv, f. 7, 1854.— Cpr. Suppl. Rep. Br. As. 1863, p. 213. 



M. t. intus, V. postica ad caudam sinuata; v. centr. unitiss., v. aiit. 



octoiissata; dent, longis, suffnltis, sa?pe extus riigosis; snbgiimdis miiii- 



inis spongiosis; sinu minimo, acuto, lam. sutur. ab apice antico solum 



sei)aratis; zoiia setifera sen lanuginosa; valvis parum postice, antice 



valde apicata; zona postice hand sen varius fissata. 



Lon. 25-GO, Lat. 15-40 mm. Div. 140°. 



i 

 Hah. — Shnmagin Islands (rare) to California ; Dall! between tide-marks 



and at lowest water. Many specimens (hundreds) examined. 



Typical form: sculpture variable, but strong; girdle thickly set with 

 tubular hairs, varying from long, strong bristles to fine, soft piloe. The 

 l)est distinguishing features are brown or blackish olive color outside; 

 inside, bluish green and lilac; jugular and caudal sinuses narrow, the 

 latter often not visible externally. 



Subsp. /?y/«os« ; sculpture faint; inside greenish; sinus variable; hairs 

 of the girdle variable, but always softer and shorter than in well-marked 

 .ciliata, often hardly perceptible in dry specimens; external colors gray- 

 ish or greenish, with streaks and liammules of brown and white. 



Yar.IIiiKlsli: exterior uniform, smoothish; sculpture evanescent; color 

 outside, light olive to nearly black; inside, whitish, carmine in the me- 



