MAZATLAK UNIVALVES 195 



253. Lepidopleurtjs clatheatus, n. s. 



L. t. suhrotundatd, depressa, (ad angulam ISO",) fusco-oliva- 

 ced ; valvis latissimis, marginibus lohatis, interstitiis suhrectis ; 

 valvis iiitermediis, injugo et (plus minusve) ioid superflde granu- 

 latts; costis diiahus, tuherculis prcevalidis miaiifis, und diagonali, 

 altered supra marginem decurrente ; areis luteralibus parvis, 

 granulans ; areis centralibus clathris iv. idroque in latere 

 longitudinalibus muni lis, elatliris fubcrculatis, interstitiis gra7i- 

 ulatts ; valvd anticd costibus radiantibus circiter xi. rotundatis, 

 suhtuberculatis ; limbo pallii latissimo, squamulis minimis, 

 moUlhus, eonferto ; marginibus valvarum sim2)licibus, antico 

 /issuris is. ad castas hand convenientibu^, testa externa, quasi 

 subgrundd, circumeunte. 



One very small specimen -sras discovered on a stone to wHeh 

 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. 



.ffa6.— Mazatlan ; imder stones, extremely rare ; L'pool Col. 

 Tablet 901 contains the specimen. 



254. Lepidopletjetjs btjllattjs, 



n. s. 



L. t. subovatd, elevatd (ad angulam 110",^ olivaced ; valvis 

 intermediis litieis diagonalibus bullis extantibus m-natis ; areis 

 lateralibus angustissimis, tuherculatis, interdum bullis munitis ; 

 areis centralibus lineis tuhercularum, in utrdque parte circiter 

 vu., lineis diagonalibus p)erpendieularibus : interstitiis tibique 

 gra7mlatis ; valvis terminalibus lineis buUarum. radiantibus 

 circiter xi., mucrone suhconspicuo ; Umbo pallii lato, pilulis 

 minimis imtructo ; valvarum lobis biangulatis, sinu alto ; 

 marginibus valvarum simplicibus, in valvis intermediis fissurd 

 lino, terminalibtis circiter vii., margine externa tegente. 



One fresh specimen (somewhat criished in extraction) and a 

 few perfect valves were found of this species, which is charac- 

 terized by the very strong row of tubercles, (hkc pebbles) which 

 lie on the diagonal line ; by the rows of somewhat strong tuber- 

 cles on the central area, running perpendicularly from the 



