288 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
intermediis valde, insculptis; arcis lateralibus seriebus granulorum a jugo 
radiantibus circiter vi.; interdum irregularibus, granis rotundatis, separa- 
tis, extantibus; areis centralibus clathris creberrimis, jugo parallelis, horri- 
dis, extantibus, interdum granulosis, ornatis; valvis terminalibus seriebus 
granulorum, circ. xx., interdum bifurcantibus, ut in areis lateralibus, 
ornatis; mucrone vix conspicuo; limbo pallii angusto, pilulis furvicaceis 
creberrimis minutis conferto; lobis valvarum bifidis, terminalibus fissuris 
circ. xi., a parte externa simplici disjectis. Long., 7; lat., 48; alt., 16 poll. 
(Carpenter.) 
Shell rather acutely carinated, the side slopes nearly straight. There 
are 17 beaded longitudinal threads on each side of the central areas, and 
from 6-7 rows of separated, rounded, erect tubercles on each lateral area. 
The lateral areas are decidedly elevated; the mucro is slightly prominent. 
The girdle has sparsely scattered hyaline short hairs. The gills continue 
as far as the front end of the foot. The outside is reddish, marbled with 
darker and white, the girdle dark ashen. The interior bluish-white. 
(Tryon and Pilsbry, Manual of Conchology .) 
Type in United States National Museum. Type locality, Cape San 
Lucas, Lower California. 
Range. San Diego, California, to Cape San Lucas, Lower California, 
and West Columbia. 
Chaetopleura lactica Dali, 1919 
Proceedings of the United States National Museum, 55:509. 
Chiton small, cream-colored, often maculated with pale green, with 
high, almost carinate back, the girdle spongy with a few small spinules 
and sparse hairs on a leathery basis; anterior valve with 8 or 9 slits, 
posterior with 2 slits, intermediate valves with single slits; anterior valve 
with about 10 feeble radii, otherwise minutely punctate-reticulate; pos¬ 
terior valve small, with subcentral mucro and similar sculpture; inter¬ 
mediate valves with the jugal and pleural tracts not separated, mucronate, 
sculptured with obliquely axial very fine threads with punctate inter¬ 
spaces; the lateral areas bounded by a slender, sometimes beaded rib in 
front and a marginal thickening behind, otherwise sculptured like the rest 
of the valve; internally whitish with a wide and shallow jugal sinus and 
prominent sutural laminae. Length, 8; width, 4.5; height, 2 mm. (Dali.) 
Type in United States National Museum, No. 172900. Type locality, 
Catalina Harbor, California. 
Range. Known only from type locality. 
[890] 
