CLASS GASTROPODA 
301 
terior margin. Central areas sculptured with longitudinal, curving riblets 
somewhat granulated. Posterior valve small, with posterior mucro, broadly 
emarginate or waved at the hinder margin. Interior bluish-white or light 
blue-green. Sinus broad and rather rounded, spongy or roughened. Sutural 
plates arcuate. Anterior valve having 8 slits, median valves 1 slit. Pos¬ 
terior valve having a broad, deep, rounded caudal sinus, and a single slit 
on each side. Girdle wide, yellow or brown, generally notched behind, 
more or less sparsely clothed with curling, strap-like, brown hairs, which 
bear near their bases a bunch of minute, white, acute spines. Length, 
46-50; breadth, 25 mm.; divergence, 125°. (Pilsbry.) 
Type in Museum of G. B. Sowerby. Type locality unknown. 
Range. Vancouver Island, British Columbia, to Lower California. 
Described as Chiton dliatus. 
Mopalia ciliata wosnessenskii Middendorff, 1847 
Bulletin, Imperial Academy of Sciences, St. Petersburg, 6:119. Tryon and Pilsbry, 
Manual of Conchology, 14:305; PI. 64, figs. 69-73. 
Chiton testa externa ovata opaca e fusco-viridescenti, straminea vel 
latericia undique seriatim tuberculosa. Valva antica et valvarum inter- 
mediarum areae laterales, radiatim tuberculosae, tuberculis quincunce 
dispositis. Radii octo tuberculorum duplo majorum prominentium, in inci- 
surae marginale sexcurrunt, dentes novem disjungentes.Valvae 
ultimae area postica tuberculorum obsoletorum seriebus concentricis, mar- 
gine postico bidentato.Valvarum intermediarum areis centralibus et 
valv. ultimae area antica longitudinaliter undulato costatis, costarum inter- 
stitiis scrobiculatis.Costae medianae, postica versus divergentes in 
summa caruna conniventes, angulorum acutorum seriem hie effingunt. 
Areae laterales a centralibus tuberculorum majorum prominentium serie 
sejunctae.Valva antica semiorbicularis dentibus marginalibus 9. 
.... Valva ultima margine postico emarginato dentibus 2. Pallium mar¬ 
ginale latum, postice bilobum, epidermide e fusco-rubicunda, setis rubicundis 
confertis crinita, obtectum. Cutis pallii, epidermide liberata, porosa. Long, 
adulti, 0.53 decim. (Middendorff.) 
Shell elongated, the back roundly arched, not carinated; dull-colored, 
varying from light olive or green to drab, generally with blackish patches 
on each side of the middle, and more or less mottled throughout with 
dusky. Sculpture much fainter than in typical ciliata. Girdle apparently 
lacking the white spicules described above. (Tryon and Pilsbry, Manual 
of Conchology.) 
Type in Academy of Sciences, St. Petersburg. Type locality ? 
Range. Unalaska, Alaska, to Santa Rosa Island, Pacific Grove. 
[903] 
