MAZATLAN UNIVALVES 199 



tentiissime longituclinaliter granulato-striato, transversim minu- 

 tissime corrugato ; areis lateraUhus indistinctis ; miperjicie 

 tota valde granulatd, tuberculis splicer oidalib us et granulis 

 eatenatim in lineis a jugo subdivergentibus elegantissime in- 

 striictd ; mucrone subconsx>ieuo, subcentrali ; intus rosed seu 

 albd ; marginibus acutis et lobis valvarum non sejniratis, mag- 

 nis,fissurd in utroque latere una, lobis angv.latis, sinu maxirno, 

 2)lanato ; ad jugum tenuissime corrugatd, ad mucronem lamin- 

 aid ; valvd posticd hexagonaU, duabus Jissuris ad tevminum 

 divisd ; Umbo pallii spictilis erectis translucidis copiose ornato ; 

 postice, antice, et ad suturas, spicularum quasi acicularum cristis 

 pulcherrime munito. 



Whetlier the varied colouring of tkis sliell, its elegant sculp- 

 ture, fhe bird-like form of tlie medial or kcxagoual shape of 

 the bifissured terminal valves, or the adornment of the mantle 

 with transparent needle-like hairs, rising now in tufts, now in 

 irregular crystals, be examined under the microscope, it would 

 be difficult to find any shell of such surpassing beauty. Only 

 one perfect specimen was found, but fresh valves belonging to 

 several other individuals were detected among the Spondylus 

 washings. The valves in the same shell greatly differ in colour, 

 as in L. albolineatus. The posterior valve is peculiarly exqui- 

 site in its form, colour and sculpture. There is considerable 

 variation in the size of the tubercles, and in the striation of 

 the jugum. The outer margin does not enclose the plates of 

 insertion, as it does in Lepidopleurus. Long. ' 16, lat. '06, alt. '02. 

 .Hai.— Mazatlan ; off Spondylus calcifer ; extremely rare ; 



Jj'pool Col. 



Tablet 907 contains the perfect specimen and 4 valves. 



Family PATELLID.E. 



Genus PATELLA, Linn. 



As the shells in this genus can scarcely be distinguished 

 from those of Acma^a, the location of many of the following 

 species in this and the next famUy is doubtful. 



259. Patella Mexicana, Brad. Sf Sow. 



Zool. Journ. vol. iv, p. 369. — Menke in Zeit.f. Mai. 1851, p. 37, 



no. 132. 

 = Lottia gigantca, B. M. : Gould ms. 

 = Patella maxima, B. M. Cat. B'Orb. Moll. p. 53, no. 443. 



