346 EXPLANATION OF PLATES. 



PLATE 52. 



14. Lorica cimolea Rv. (=volvox Rve.). Conch. Icon., . 237 

 15. Lorica volvox Rve. Ross del., ..... 237 



16. Lorica volvox Rv. (1 sq. mill, of girdle). Pilsbry del., . 237 



17, 18. Lorica volvox Rv. (posterior valve). Pilsbry del., . 237 



19, Lorica volvox Rv. (anterior valve). Pilsbry del., . . 237 



20, 21. Lorica volvox Rv. (intermediate valve). Pilsbry del., 237 



22, 23. Enoploctiton niger Barnes (posterior valve). Emer- 



ton del., 252 



24, 25. Enoplochiton niger Barnes (intermediate valve). 



Pilsbry del., . 252 



26. Enoplochiton niger Barnes. Ross del., .... 252 



27. Enoplochiton niger (surface). Q. J. M. S., . 252 



28. Enoplochiton niger (surface). Q. J. M. S., . . 252 



29. Enoplochiton niger (girdle of a young specimen). Emer- 



ton del., . . . . ... 252 



PLATE 53. 



30. Liolophura incana Old. ( L. gaimardi Blv.). IT. S. Expl. 



Exped., . 240 



31. Liolophura gaimardi Blv. (girdle spines). Pilsbry del., . 240 



32. Liolophura gaimardi Blv. Ross del., .... 240 

 33-35. Liolophura gaimardi Blv. Pilsbry del., . . .240 

 36-40. Liolophura georgiana Q. & G. Voy. Astrol., . . 241 



41. Liolophura japonica Lisch. (Girdle spines). Pilsbry del., 242 



42. Liolophura japonica Lisch. Ross del., . . . 242 



43. 44. Liolophura japonica Lisch. Jap. Meeres-Conch., .242 



45. Liolophura japonica var. tessellata Pils. Ross del., 



46. Liolophura japonica var. tessellata Pils. Pilsbry del., .243 



PLATE 54. 



21, 22. Nuttallina scabra Rv. Pilsbry del., . . . .280 



23, 24. Nuttallina californica Nutt. Pilsbry del., . . 279 

 25-27. Nuttallina alternata Sowb. Conch. 111., . . .281 

 28-30. Nuttallina cinerea Poll. Emerton del., . . . 283 



31. Nuttallina cinerea Poli (edge of girdle x 100). Pilsbry 



del., 283 



32. Nuttalliua cinerea Poli. Test. Utr. Sic., . . . .283 



33. Nuttallina cinerea Poli (girdle x 50 ca.) Pilsbry del., . 283 



34. 35. Plaxiphora ovata Hutt. Pilsbry del., . ' . . 332 

 36-39. Plaxiphora ovata Hutt. (profile, posterior, dorsal and 



ventral views of posterior valve). Pilsbry del., . . 332 

 40. Plaxiphora ovata Hutt. (sculpture of intermediate valves). 



Pilsbry del., 332 



41-45. O. caliginosus Cpr. (=Liolophura japonica Lisch.) 



Emerton del., . 244 



46. Onithochiton amicorum Bd. Voy. Curacoa, . . . 249 



