117 



elongato-ovata, vix carinata, sraaragdina ; area centrali liris lon- 

 gitud. pectinata ad* apicem lrevi ; areis lateral, elevatis, liris 

 ramosis nodulosis instructis ; valvis terrainalibus magnis prope 

 marginem radiatis, umbone subcentrali ; ligamentum latum, squa- 

 mis magnis ti-ansversis convexis obtectum. Long. 25, lat. 15 

 millim. Hab. 



C. (Leptochiton) comptus. T. parvula, tenuis, elliptica, aut 

 viridis aut incarnata sa^pe albido vel flavo varie fasciata punc- 

 tata vel maculata ; valvis brevibus, terminalibus radiatim costatis 

 etiam punctatis, area centrali quincuncialiter punctata ; areis late- 

 ralibus elevatis et sulcis radiantibus 4-5 insculptis ; intus viri- 

 dans ; ligamentum angustum squamis parvis elongatis sulcatis 

 imbricatum. Long. 15, lat. 10 millim. Hab. Ousima, Bonin 

 and Loo Choo Is. W. S. 



In form like squamulosus and rugulatus, but sculptured differ- 

 ently ; possibly G. caliginosus Rv. 



C. (Leptochiton) Jacobjeus. T. parvula, cinerea, elongata, 

 elliptica vix carinata ; valvis terminalibus permagnis, fornicatis, 

 costis scabris radiantibus ad 10 ornatis ; area centrali cancellata ; 

 areis lateral, conspicuis, bicostatis ; ligamentum angustum, squa- 

 mis minutis elongatis obtectum. Long. 12, lat. 5 millim. Hab. 

 Simoda. W. S. 



The vaulting and ribs of the two large terminal valves make 

 them resemble two small Pectens. 



C. (Leptochiton) concinnus. T. minuta, rubida, elliptica, 

 fornicata, omnino punctata, punctis seriatim dispositis, seriebus 

 radiatim flectantibus ; areis lateralibus haud elevatis, longitud. 

 undulatis ; valva antica crescentica ; v. postica acute umbonata 

 concentrice undulata ; ligamentum angustum, lutescens, pruino- 

 sum. Long. 8, lat. 5 millim. Hab. Hakodadi. W. S. 



In size and form like 0. albus, but sufficiently distinct by its 

 evident lines of punctures. 



C. (Leptochiton) craticulatus. T. tenuis, fusco-cinerea, 

 lata, elliptica, admodum carinata ; area centrali longitud. clath- 

 rata, clathris elevatis, acutis ; areis lateral, angustis, elevatis, 

 liris eminentibus asperis divaricantibus 4-8 instructis ; valva an- 

 tica erescentica radiatim lirata ; v. postica vix umbonata r^diata ; 



