798 PROCEEDINGS OF THE NATIONAL MUSEUM. vu...xxiii. 



the lig-ament and resilium large, deeply inset, the former with an exter- 

 nal calcareous coating- margins entire; foot moderatel}" elongated but 

 not lorit'orm. 



Dental formula: ,^ , * ,^^^- — , • Type, Chanui codok Adanson. 

 K olo. 0101. olo 



The posterior lateral teeth are obscured by the growth of the liga- 

 ment in the adult, but traces of them can almost always be noted. The 

 cai'dinals are not bifid and the anterior right cardinal is often obscured 

 by the excayation of the lunule in front of it in the adult, "v 



Jagonia Recluz. Shell smaller, lighter, frequently tumid and yery 

 inequilateral; beaks more prominent and the lunule, relatiyely, often 

 larger; ligament and resilium external, on a narrow nymph, not coated 

 with shelly matter; posterior laterals distinct; margins usuall}" crenu- 

 late; foot differing little from the ordinary Pelecypod tj^pe. Type, 

 Le jogon Adanson, = Yenus orhiculata Montagu + Luclna jhicteii 

 Lamarck. 



In these forms the radial part of the sculpture is relatiyely more 

 pronounced than in iJodakia. The name Ctena of Morch would have 

 precedence oyer Jagonia if not regarded as preoccupied b}" the prior 

 use of Ctenia in entomology. 



In the typical diyision of the genus C. j';?/;?t^?'(;/to and C. tlgei'ina 

 Linnteus (as Yemis^ 1T58) are P^ast Indian and Indo-Pacific, C. orhicu- 

 lark Linmeus is Antillean, and a distinct species, here described, is 

 found on the Pacific coast. These haye been lumped together by 

 most writers hitherto to the great confusion of the nomenclature; 

 though, as Han ley pointed out half a centur}^ ago, Linn^us himself 

 originally discriminated the three first mentioned and assigned the 

 true localities to them; though he afterwards confounded the second 

 and third. A similar confusion has, with more excuse, attended the 

 names of the more common species of Jagonia.^ 



It is possible that when we know more about them some of the small 

 species, here referred to, Jagonia may require a separate section for 



' The Mediterranean ppecien, long confounded with the Liicina pecten of Lamarck, 

 is the Tellimi. reticulata of Poli, 1798, not of Linnfcus, 1766; the Luclna reticulata oi 

 Payraudeau, 1826, not of Lamarck, 1818 {=Semele sp.); the Luclna squomoKa and 

 pecten of authors, but not of Lamarck; the Luclna decussata of Costa, 1830; and, 

 accf>rding to Dautzenberg (Moll, de Roussillon) the Luclna carnarla and miralillls oi 

 Locard, 1892. The latter is not the L. wlrabllis of Dunker, 1865, which is Mlltha 

 Voorhwrei Deshayes, 1857, from Mozambique. The Mediterranean shell must then 

 take the name of Codakia {Jagonia) deeussata (Costa). 



The common Indo-Pacific species has almost as complex synonymy, having been 

 first described from specimens probably collected at the Sandwich Lslands by 

 Nuttall, but erroneously referred (like some other species of Nuttall) to San Diego, 

 Californii, where no Jar/oiila exists. It is the Luclna heJla Conrad, 1837, not of Car- 

 penter, 1857; L. fil)ul(t (part) Reeve, 1850; L. ramulosa Gould, 1850; L. dlrergens of 

 P)iilij)pi, 1850; and has been referred to L. sfpiamom and L. pecten of Lamarck by 

 many authors. The name Codakia {Jagonia) bella (Conrad) must be retained for it. 



