225 



In this species the margins of the lozenge or ligamental area are 

 acute, and the ligamental fossa is protected on each side by a pro- 

 duced lamina ; the lunule is very deep and nearly triangular, and the 

 concentric striae on the valves seem to be undulated on account of 

 the impressed grooves which radiate from the beaks. 



17. Lucina lactea, A. Adams. L. testa crassa, orbicular i, sub - 

 ventricosa, lactea, vix obliqua, concentrice lamellcsa, Inmellis 

 distantibus, regularibus, interstitiis striis elevatis, radiantibus, et 

 lineis transversis decussatis, umbonibus fere medianis, prominulis ; 

 latere antico rotundato, subtruncato, et subangulato ; postico 

 rotundato ; cardinis dente apicali antico, lato, prominente ; intus 

 incrassata alba, margine ventrali crenulato. 



Hub. Swan River {Br. Bacon) ; New Zealand (Mr. Strange). 

 Mus. Cuming. 



A peculiar species, having somewhat the aspect of a Corbis, but 

 without any lateral teeth, and with the anterior primary tooth of one 

 valve very broad and dilated. 



18. Lucina (Codakia) munda, A. Adams. L. testa lenticulari, 

 convexiuscula, aquilaterali, albida, costulis radiantibus, dichotomis, 

 ad latera divaricantibus, ornata ; concentrice imbricato- striata ; 

 umbonibus medianis, minutis, anteversis ; lunula excavata, intus 

 lutescente ; margine ventrali radiatim sulcato ; cardinis dentibus 

 apicalibus duobus, divergentibus, lateralibus, validis. 



Hab. Moreton Bay (Mr. Strange). Mus. Cuming. 

 A very neatly sculptured species, with dichotomous radiating ribs, 

 and with the inner margin of the valves radiately grooved. 



19. Lucina (Cryptodon) plicifera, A. Adams. L. testa 

 subquadrato-ovali, cequilaterali, subcompressa, sordide alba, epi- 

 dermide fusca, tenui induta, concentrice plicata, plicis tenuibus, 

 distantibus, latere antico margine sinuato, sulco obliquo, ad mar- 

 ginem extendente, impresso ; latere postico obtuse angulato, mar- 

 gine subtruncato ; lunula elliptica ; cardinis dentibus apicalibus 

 nullis, dente laterali antico instructo ; intus alba. 



Hab. Borneo. Mus. Cuming. 



This is a plicate species in which the primary teeth appear to be 

 obsolete or wanting, and where there is only a single lateral tooth in 

 each valve. This belongs to the form to which the name Cryptodon 

 has been given. 



20. Lucina (Myrt^ea) layardi, A. Adams. L. testa lenti- 

 culari, solida, convexiuscula, alba, aquilaterali, costulis radian- 

 tibus, subnodoso-squamosis, ornata, concentrice sulcata, umboni- 

 bus minutis, centralibus, latere antico costis imbricato-lamellosis, 

 postico superne rectiusculo ; intus Candida, margine ventrali crenu- 

 lato, intus radiatim sulcato. 



Hab. Ceylon (E. L. Laijard, Esq.). Mus. Cuming. 



In form and sculpture this specie^ very much resembles L. (Mijr- 

 t<ea) Strangei, but it is much more compressed, and the radiating 

 ribs are more nodose than scaly. 



