ox MOLLUSCA OT THE WEST COAST OF NORTH AMERICA. 



eio 



Nutt. Jew. B.A. Smiths. Ins. Ken. Lord. Swan 



220. Acaiithopleura scabra .... 



^;21. iliixa ; 



222. Ischnocliiton Magdalensis 

 •223. veiedeutieus 



224. Lepidopleurus regularis . 



225. scabricostatus 



220. pectiuatus 



227. Mertensii 



228. Tracbydennon retiporosus 



229. interstinctus 



2:W. tritidus 



231. deutiens 



231 h, pseiidodentieus . , 



232. Gotbicijs 



233. ITartwegii 



234. Nuttallii 



235. tiecteus 



M 



M 



C 

 L 



C 



C 

 P 

 P 



FI 

 LM 



M P 



— P 



Cooper. 



C 11 F 

 C M 



— M 



I 

 I 



DI 

 I 



I 

 I 



— V 

 V — 



D 

 I 



I 

 D 



220. 

 221. 

 222. 



223. 



224. 



225. 



22G. 

 227. 



228. 



229. 

 230. 

 231. 

 231 



Acanfhopleura scahra, Rve. = CaUfommts, Nutt. Insertion-plates resemble 



Katherina. Valves witb coarse V-sbaped ribs, and projecting beaks. 

 Acanthopleuraflm-a, n. s. Green, mottled with orange-red ; not beaked ; with 



only marginal and diagonal ribs. • t o t j- „.„^i, 



TschlchiionMaridalensilYU.. Large, strong-valved, typical Sculpture mc^ 



lainter than in southern shells. Mantle-margm ^v-Uj stnated scales like 



flattened bristles. Side plates 2- or 3-lobed Beach-20 fm Cp. 

 Lchwchiton veredentiem, n. s. Margin similar. S"^f '/^^f '^'.f "]P^"lf 



like Mertensii, but with 2 rows of bosses, one of which dentates the suaues. 



^^:i!!^-m^egrdans, Cpr. P. Z. S. 1855, p. 232. Sul.genus oi Isc^ncMn: 

 mantie-scales Lophvroic( generally striated. Sp. arched, green, shagreened. 

 Side lobes 2-4 : eaves spongy, not projecting. . 



Dpidoplcnrus scabricostatm, n. s. Small arched orange : rows of Fomment 

 granules over shagreened surface. Lobes blunt, slightly rugulose, CxO.e to 



jJS/m^m^.S»m£.s n. s. Olive: strong sculpture over shagi-ee^ed siu-face: 

 side areas ribbed : outer margin and inner sutures pectinated. Bch. Lp. 



Lepidonk'ums 3Ic>iensii, Midd. Red : highly sculptured over smooth surface . 

 4de areas with rows of bosses. Mantle-scales smooth, rounded. 



Trachydermon retiporosus, n. s. Subgenus of Ischnochton- "mantle-scales very 

 small, close, smooth. Sp. like scrohwulatus, central pattern m netwoik, 3-0 



Tmchydermon interstinctus, Gld. E.E. Centre minutely punctured : 6-8 blunt 



Traek^iermon trifdus, n. s. Centre-punctures few, deep : 2-4 blunt ribs : side 



r rS^'^'^o^^ tS^>«s, Gld. E.E. No shell known answering to diagnosis and 

 \_iiuuujHt, u ,..._._ _,^^.-,„ 1 ^,,^ inmsavs bimt. eaves not nroiecTing. 



232. 

 233. 

 234. 

 235. 



fioure 1 The 4 following species have incisors blunt, eaves not proj ecting. 

 b Tiaclndermon pser^dode,itiem^iy^^ specimen oidentiens False appearance of 

 teeth due to colour or ridges of gTOwth. Closely granular : areas indistinct. 



Sinus broad, squared : eaves spongy. i. j v i 



TrZnidermon Gothiens, n. s. Blunt parallel riblets along verv arched back. 



Sutural lobes united at sinus : eaves not spongy 8-20 Im. Lp 

 Trachydermon Hariicegn, Cpr. P. Z. S. 1855, p. 231. Large, arched. In.ide 



callous, without rows of punctures to slits : eaves spongy. 

 r'^Sydlrmon Nattcdiii, Cpr. P. Z. S. 1855, p. 231. Large, plain, flat. Incisors 



slio'htlv rugulose : eaves spongy. 

 Trachudernion fiectens, n. s. Mantle-margin scarcely granular. Rosy, very 



small, scarcely sculptured: valves beaked and waved as m M. Simpsonn: 



eaves and incisors normal. 



