\ 
MAZATLAN UNIVALVES 195 
253. LEPIDOPLEURUS CLATHRATUS, 7. S. 
LL. t. subrotundata, depressd, (ad angulam 130°.) fusco-oliva- 
ced; valvis latissimis, marginibus lobatis, interstitiis subrectis ; 
valvis intermediis, in jugo et (plus minusve) toté superficie granu- 
latis; costis duabus, tuberculis prevalidis munitis, und diagonals, 
alteré supra marginem decurrente ; areis lateralibus parvis, 
granulatis ; areis centralibus clathris iv. utrogue in latere 
longitudinalibus munitis, clathris tuberculatis, interstitiis gran- 
ulatis ; valvd anticé costibus radiantibus circiter i. rotundatis, 
subtuberculatis ; limbo pallii latissimo, squamulis minimis, 
mollibus, conferto; marginibus valvarum simplicibus, antico 
fissuris 1x. ad costas haud convenientibus, testa externa, quasi 
subgrundé, circumeunte. 
One very small specimen was discovered on a stone to which 
a Crucibulum had been attached, beautifully perfect except in 
the loss of the anterior valve. A dead anterior valve was found 
of a much larger specimen, displaying a marginal structure like 
that of L. sanguineus. The shell is remarkable for the strong 
bars across the ventral areas, and the stout rows of tubercles 
which run, the one diagonally, the other along the interstitial 
margin. The mantle is very broad, and crowded with minute 
scales. Long. ‘17, lat.°12, alt. ‘02. 
Hab.—Mazatlan ; under stones, extremely rare; L’pool Col. 
Tablet 901 contains the specimen. 
254. LEPIDOPLEURUS BULLATUS, 7%. Ss. 
LL. t. subovaté, elevaté (ad angulam 110°.) olivaceé ; valvis 
wntermediis lineis diagonalibus bullis extantibus ornatis ; areis 
iateralibus angustissimis, tuberculatis, interdum bullis munitis ; 
areis centralibus lineis tubercularum, in utrdque parte circiter 
vil., lineis diagonalibus perpendicularibus : interstitiis ubique 
granulatis ; valvis terminalibus lineis bullarum radiantibus 
_etrciter X1., mucrone subconspicuo ; limbo pallii lato, pilulis 
minimis instructo ; valvarum lobis biangulatis, sinu alto ; 
marginibus valvarum simplicibus, in valvis intermediis joes 
uno, terminalibus circiter vi., margine externo tegente. 
One fresh specimen (somewhat crushed in extraction) and a 
few perfect valves were found of this species, which is charac- 
terized by the very strong row of tubercles, (like pebbles) which 
lie on the diagonal line ; by the rows of somewhat strong tuber- 
eles on the central area, running perpendicularly from the 
