136 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 23 



Hinnites multirugosus Gale. Fitch, 1953, p. 41, fig. 7. "Queen Char- 

 lotte Islands, British Columbia, to Abreojos Point, Baja Cali- 

 fornia." — ^Abbott, 1954, p. 369. Aleutian Islands to Lower Cali- 

 fornia. 



Holotype: British Museum. 



Type locality: Juan de Fuca Strait (between Vancouver Island, 

 British Columbia, Canada, and the state of Washington, U.S.A.). 



Original description : Testa crassa, ponderosa, subauriculata. Albido- 

 rosea, irregulariter radiata costata striata; intus alba, rufo maculata. 

 Lat. 15-4, long. 18-4 unc. 



Additional description: Shell large, heavy, and irregular in outline 

 when adult; averaging 105 to 150 mm in height, occasionally much 

 larger; ratio of height to length variable, but almost always higher than 

 long. 



Juvenile form (up to from 20 to 30 mm in height) : identical with 

 Chlamys ; slightly higher than long ; valves of nearly equal convexity ; 

 hinge line from ^ to % length of disk. Right valve with numerous low 

 and finely imbricated ribs, which become dichotomous early and appear 

 to be paired, particularly near ventral margin ; specimens up to about 

 15 mm in height have distinct intercostal concentric lamellae, which 

 disappear soon thereafter. Anterior auricle long, often produced as far 

 as anterior margin of disk; 6 to 11 concentrically lamellated radial 

 riblets; deep byssal notch and ctenolium of 5 teeth. Posterior auricle 

 Yz to y2 length of anterior and with faint, oblique, imbricated radial 

 riblets. Left valve with 10 or 11 ribs, moderately to prominently spinose; 

 between them 3 to 5 imbricated riblets, with either center one of three 

 or second and fourth of five slightly larger. Anterior auricle large, with 

 12 to 20 imbricated radial riblets of irregular size; byssal sinus usually 

 shallow ; posterior auricle same as that of right valve. Color range in- 

 cluding deep to pale brown, red-orange, orange and yellow; left valve 

 often mottled or streaked with darker and lighter colors; right valve 

 either much lighter than left or white ; purple-red stain appearing around 

 resilial pit when shell reaches 10 to 15 mm in height. 



Adult form: large, heavy and irregular; juvenile Chlamys stage 

 preserved intact on each valve, succeeding growth being much heavier 

 and coarser. Shell attached by right valve to rock (or other foreign 

 object), by means of shell substance secreted by outer lobe of mantle of 

 that valve; moderately to greatly distorted (both laterally and hori- 

 zontally) as result of conformation to surface of fixed object and, in 

 many cases, restriction of space in which to grow. Right valve quite 



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