304 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



Mopalia ciliata. 



Chwtopleura muscosa Gould, Otia, p. 242, 1862. 



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



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



part of diagnosis excl. 

 Chiton armalus (Nutt.) Jay, Cat. 1839, No. 2078. No descr. 

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

 Chiton confiimilis Nuttall, MS. loc. cit. never described. 



Subsp. Mopalia lignosa. 



Chiton Jignos)is Gould, Proc. Boston Soc. Nat. Hist, ii, p. 142, July, 1846 ; Otia, p. 



3, 1862 ; Exp. Sh. p. 330, f. 424, 1852. 

 Chatopleura lignosa Gould, Otia, p. 248, 1862. 

 Mopalia lignosa Carpenter, Suppl. Rep. Br. As. 1863, i>. 048. 

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



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

 Chiton Eschscholtzii Midd. Bnll. 1. c. p. 118 ; M:il. RoSs. 1. c. p. 114, pi. xi, f. 4-(t. 



juu.). 

 Chiton (Hamaehiton, Stenoscmus) Merckii Midd. 1. e. p. 34. 

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



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

 Chatoplcnra vespertina Gould, Otia, pp. 230, 242, 1862. 

 Mopalia vespertina H. & 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 californiais (Nutt. MS.) Reeve, Conch. Ic. Mon. Chiton, pi. xvi, f. 89, 1847. 

 Var. M. Hindsii. 



Chiton Hindsii (Sowerby MS.) Reeve, Conch. Icon. ^fon. Chiton, pi. xii, f. 67, a, 



ft, 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. iutus, V. postica ad caudam sinuata; v. centr. nniflss., v. ant. 

 octoflssata; dent, longis, snffiiltis, saei^e extns rugosis; siibgnrndis mini- 

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

 separatis; zona setifera sen lanuginosa; valvis pantm postice, antice 

 valde apicata; zona postice hand sen varius fissata. 



Lon. 2o-G0, Lat. 15-40 mm. Div. 140o. 



Sal). — Shumagin Islands (rare) to California; Dall! between tide-marks 

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



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

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

 best 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. %Jios«; sculpture faint; inside greenish ; sinus variable ; haii^s 

 of the ghdle variable, but always softer and shorter than in weU-marked 

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

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



Yar. Hindsii : exterior uniform, smoothish; sculi)ture evanescent; color 

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



