-105- 



C^^" 



ARGA (GALIOAP.GA) DEIj:PI.DA n. sp. 



Pesoript ion .- ^hell small, moderately elongated, well inflat- 

 ed; anterior end rounding rapidly into the iDase ; base almost straight 

 very feebly emarginated ::Tedially, flexed upward at the posterior 

 end; posterior mar~in produced below, obliquely truncated above; 

 umbones conspicuous, broad; posterior ridge rounded; external 

 sculpture consisting of mxmerous, fine radial ribs, ornaroented with 

 conspicuous, delicately sculptured, square or slightly elongated, 

 nodules throughout; as usual, anteriorly and posteriorly the 

 ribs and interspaces wider, esoecially on the posterior slope; 

 cardinal area ivide for the size of the shell, with obscxu-e trans- 

 verse striations in the anterior and me-'ian regions and deeper ob- 

 lique grooves postei'iorly ; hinge-teeth forming a continuoiis series, 

 the teeth relatively heavy, normal in position; anterior and post- 

 erior inner margins obscurely crenulated. 



Di'-:!ensions .- Llax. length, 6„5 nan.; alt. 4.2 mm.; semldiam., 

 1.8 mm.; length of hir^ge, 5 mm. 



Remarks .- The distingiushing feature of this species, which 

 also is represented by only a Gin^^le valve, is the delicate, ret- 

 iculated sculpture, by which feature alone it may be separated 

 from the associated ^alloarcas. Because of the character of the 



