CLASS GASTROPODA 
311 
Mopalia heathi Pilsbry, 1898 
Proceedings, Philadelphia Academy of Natural Sciences, 288. 
Oblong, rather elevated, carinated, with nearly straight side-slopes; 
surface smoothish to the naked eye, lusterless, and in color (1) olive-green 
with some lighter spots, or purplish maculation, or slight roseate suffusion, 
or (2) vivid red, with scattered blue spots. Valves shaped as in M. lignosa, 
but without a median anterior projection of the tegmentum; the inter¬ 
mediate valves very faintly radially triculcate at the sides, the anterior two 
grooves defining the low, slight, and inconspicuous diagonal rib, the lateral 
areas not raised; entire surface very finely and evenly granulate, the 
granules small, rather pointed, separated, intervals very minutely, radially 
wrinkle-granulate. Anterior valve with a few faint, shallow, radial fur¬ 
rows. Posterior valve with semicircular posterior outline, the mucro in 
front of the middle of tegmentum, profile of the surface in front of it 
convex, that of the posterior slope decidedly concave. Interior deep rose 
color or slightly purplish; sutural laminae and sinus about as in lignosa. 
Teeth rather long and somewhat roughened, as in lignosa . Valve i with 8 
slits; ii-vii with 1-1; valve viii entirely Ischnoid, with regular, cres¬ 
centic insertion plate, cut by 7 or 8 slits, which are somewhat closer pos¬ 
teriorly; no sinus behind. Girdle leathery, nude except for solitary or 
two or three closely grouped long bristles at all or part of the sutures, 
one on each side of the head valve, and two behind the tail valve. Gills 
about 25 on each side, not extending quite to the anterior end of the 
foot. Length, 25 ; width, 12 mm. (dried specimen), or smaller. (Pilsbry.) 
Type in Philadelphia Academy of Natural Sciences. Type locality, 
Pacific Grove, near Monterey, California. 
Range. Monterey, California. 
Mopalia chloris Dali, 1919 
Proceedings of the United States National Museum, 55:513. 
Chiton low, wide, of moderate size, of a dark bronze green, with 
leathery girdle which when fresh had a few slender, sparsely distributed 
hairs upon it (lost in the dry specimen) ; anterior valve with eight slits, 
externally with about ten radiating, conspicuous threads with a few feeb¬ 
ler, shorter, intercalary threads, over the whole of which is a faint, very 
minute, oblique decussation; posterior valve small, with a very low sub¬ 
central mucro and a faint concave wave medially behind, over which is a 
white ray; it has two slits and a narrow rounded jugal sinus with wide 
sutural laminae, the finer sculpture is like that of the anterior valve with 
[913] 
