690 REPORT— 18G3. 



Plnte Fie. No 



IV. .'U. 20. Tapes dirersum, Sbv. [=T<ippx sfamiiun, Conr., TJir. Pififti, 

 (III. intext). Desh.] Kftent formation. San I'edru. 



III. 25. 27. 'Saxicara afini/iia, Conr., n.s. [Probably the shortened farm of 



Pcfrico/d ranfitoidcs, Conr.] Ilecent formation. San I'imIvo. 

 ff 24. 28. I'etricula PednHiua, Conr., n.s. [Allied to P. vetUricosa, 1)l's1i.J 

 lifcent formation .Sau Pedro. 



IV. 33. 29. Schizothcenis yiit1(dli,Com.,''n.a:'^Tresiiscapax,G\&. Recent 



formation. San Pedro. 

 III. 23. 30. fLufran'a Traskci, Conr., n.s. [Not improbably = Saxidomiis 

 Xidfallii, {.'out., ^UQ.^ !-'Miocene. Cannello. 



V. 45. 31. Muctra DicyiHina, Conr., n.s. Like M. allniria, of the Oregon 



Miocene. [Resembles MuUntu an(julata,ijrAy.~\ J" Miocene. 

 San Diego. 



„ 35. ,32. 3Iodio/a coidracf a, Conr., n.s. [Very like Jf. rec^a, ^onr.] ?Mio- 

 eene. Monterey Co. Recent formation. 



„ 40. 33. Mytilus Pcdrvanus, Conr., n.s. [Probably = 3/. edulis, jun.] 

 Recent formation. San Pedro. 



,, 41. 34. Pecten Desciii, Conr., n.s. [I{e.«embles P. circularis.'] Mio- 

 cene. Cjirrizo Creek, Colorado Desert. 



f, 34. 3'5. Anoiuia .mhcjutafa, C<>r)r.,n.>*. \y = Placunanomia m(croschisma.'\ 

 Miocene. Coloratlo Desert. Allied to A. Ptiflim. 



ff 30-38. 30. Odrea venpeiiitia, Conr., n.s. [Resembles O. lurida, var.] Mio- 

 cene. Colorado l>esert. Like O. suhfulcata, Conr. 

 37. Odrea Ileeniiuiini, Conr., n.s. Colorado Desert. 



„ 43. 3S. Priiittlla spvlmi, Conr., n.s.* Recent formation. San Pedro. 



„ 44. 39. Fmurclla crenidaki, Sby. \_ = Lucuj)iiia c] Recent formation. 

 San Pedro. 

 VI. 52. 40. CrepuUda princepg, Conr., n.s. [= C. grandis, Midd.] Recent 

 formation. Santa Barbara. 



V. 39. 41. Xarica IJieyoann, Ccmr., n.s. ? Miocene. San Diego. 



„ 42. 42. Tntrhifu Diet/oaufi, Voni:, n.s. [Like T. vetitncosa ; but may be 

 Go ferns contort Hs.] •'Miocene. San Diego. 



„ 40. 43. CrKcibidK?n .'ipinnstim, Conr., n.a.f Recent fonnation. San Diego. 

 VI. 49. 44. Xa.ssa iHterstriata, Conr., n.s. [=iV". meudica, Gld.J. Recent 

 fomiation. San Pedro. 



„ 48. 45. NaxHi Pedroana, Conr., n.s. [Comp. Amycla gmisapata and it3 

 congeners.] J Recent fornia<^ion. San Pedro. 



„ 51. 40. Strephona Pedroana, Com., n.s. [Comi^. Olivelia beetica.'] Recent 

 formation. San Pedro. 



„ 50. 47. Litorhia Pedroana, Com., n.s. [ = i. ^)fc/ja, Gld.] Recent forma- 

 tion. San Pedro. 



f, 47. 48. Stramonita pefrosa, Conr., n.8. [Is perhaps Monoceros lugubre.'\ 

 ? — . Tulare Valley. 



* Mr. Conrad regards the " coriaceous cup as chBracteristic of the genus." It appears 

 a subgenus of Pho I ad idea, diffLTing m the form ot the plate. Mr. Tryou, "Men. Pho- 

 lad.," p. 66, restricts it to the Penitella penita, wliich (according to liis di&gnosis) has 

 one central and two anterior dorsal plates. The closely related P. m^oidea he leaves in 

 the original genus, as having " two dorsal accessory valves," although he allows that " its 

 position cannot be accu; itely determined on account of the loss of its dorsal valves." 

 Conrad's fossil has the shape of P. ovoidea ; but although he says that it is " widely dis- 

 tinct" from P. penita, I am unable to separate it from the ovoid form of that species, 

 which will be found in the Smitlisonian series. 



t This is certainly Sowerby's species, to which Conrad gives a doubting reference. In 

 Uie text he gives it as " fpinosum, Conr.," in his table marking it as " nov. sp." 



* Conrad compares A*, intemtriata to N. trivittata,S&y, and N. Pedroana toN. lunata, 

 Say.and states that the two Atlantic species ai-e "associated with each other both in the sea 

 and in the Miocene deposits of Virgima and Maryland." As the two correlative speciea 

 are fo'ind tot^ether, hving and fossil, on the Pacific iide, tliere is presiunptive evidence for 

 their Imvmg desceudeu from a cuuimon atocii. 



76 



