275 DR. p. p. CAnPKNTER ON NEW SPECIKS 



{ — J.ppidojtlt'iiiun, Add.,) known by the sharp intisor-tccth Iviiig 

 within a jimji ctins; hp, tlure are three typrs of niiinth-inarj;in, 

 which may lie conveniently separated as suhj;enera, to aid in the 

 diltieult ta>k of de>erihin;r and iiientilyinj; species. Tlie typical 

 forms, forwliich tlie wnmv I«vlinovhit on shoidd he retained, have the 

 scales somewhat chaffy, and \ery finely striated. /. iiuir/ilalensia 

 and I.sdtiijdiiicus well represent the group. But another series have 

 the mantle-scales imbricate and strong, as in Chiton, Gray, { = Lo- 

 j)hijrt(!>. Add.,) from which tiiey cannot be distinguished without 

 ilissection. For this Messrs. Adams's name Li'jii(/ojj/ti>rus may be 

 retained in a restricted sense. It is uncertain what ISisso's oriyrinal 

 genus was meant to include : his diagnosis apjilies to all Chitons 

 with distinct side-areas and scaly margins. 



A third group, separated by Dr. Uiay in his 'Guide,' p. 1S2, aa 

 having the " mantle-scales minute, granular," has been named Tra- 

 chiidernion : it abounds in the Californian region. 



The sfiecimens of L. ailamsii were found among the duplicates 

 named ( hiton dispar by the I'rofessor ; one was attached to Dincina 

 citminyii, 



Lepidoplevrus tenuisculptus. 



L. t. " L. .idamsii " siini/i ; oUcacea, colore pallitio seu intensior? 



minute variefjata ; tota siiperfiric mirnite granulosa ; arna 



later(ilibi(s ci.c dejinitis ; siituris jtlerinnqiie iilhidu nidculafis; 



mucrfiie antico, satis cotisjiicuo, parte puslica cuncaca : intus, 



%d in " L. in]nmsl\" foniKita. 

 Vaiiat : '. palliilore, ad juyuni rvfo-tincta. 

 = Chitoii ilispar, C. B. Ad. no. 373, pars. 



The outside of this shell so much resembles the young of Chifor, 

 (Lop/ii/rus) sto/iesii, that specimc.io may hav-. been distributed undti 

 that name. Very few individuals were foui.d. 



IscHNOCHiTON ELENENSis (diagn. aucc). 



£xtus areis centralihus cinthris parallel is circ. xx. decvssatis , 

 ar. lat. costis ii., validmrihits, tiimidis, tuherridosis : intus 

 mar^iniljus suturalihus ponlicis rejiexis, tuberculatis, sinu ad 

 juyvm parvo ; luminis inserlionis unijissis, ad laminas sutu- 

 rales an/ires Jnnctis, sinu latissinto. Vulva antica ewtus costis 

 xii., kaud rulidis ; inius Jissuris x., deutiius acufis, subyrvnda 

 parvu. T'ali'a postica mucrone subpostico, depresso ; parte 

 2)ostitd ejpansa, concava, costis circ. xi. subobsoletis ; intus 

 lamina insertiouis circ. \\.-Jissa, dentibus curtis, subyrunda 

 parva, intus callosa. 



The central valves in this species are normal ; but the posterior 

 valve offers a transition towards Callochiton, the outside being con- 

 cave posteriorly, the insertion-teeth short and the eaves callous. 



ISCHNOCHITON (? Vaf.) EXPRESSUS. 



I. t. "I. elenensi" simili, sed carnea ; areis centr. cJuthris x., 



266 



