576 MR. S. HAN LEY ON THE GENUS LEPTOMYA. [JunC 20, 



5. On the Genus Leptomya (A. Adams). 

 By Sylvanus Hanley. 



[Keceived June 13, 1882.] 



The little genus Leptomya (which, despite my aversion to the multi- 

 plicity of names induced by the unnecessary division of established 

 genera, I regard as a natural and a useful one, because its members 

 cannot be placed elsewhere) was briefly characterized, in English, by 

 Arthur Adams in 1864. Reference was made to only two species, 

 both so cursorily described that it was almost impossible to determine 

 them, as neither had been figured. Of the first, regarded as an 

 abnormal Necera by Hinds (N. cochlearis. Hinds), only a single 

 valve had been previously taken. It is not absolutely positive that 

 the second (Scrobicularia adunca of Gould) may not prove identical, 

 although the description by Hinds is more applicable to another 

 species than to his own type. The genus was also limited to these 

 two by Tryon, in his useful catalogue of Bivalves, in 1869. In the 

 Linnean ' Proceedings ' I have published the characters of a third 

 species, L. gravida ; and now I know at least two others, which I here 

 characterize. 



Leptomya psittacus, sp. nov. 



T. suhcequilateralis, nivea,fragilis {sed opuca), acuminato-obovata 

 (yel rotnndato-ovata), antice late rotundata,postice acute angu- 

 lata et breviter sed conspicue rostrata, ad umbones ventricosa, 

 rostrum versus concava et compressa, sublavigata, maryines 

 versus autem rugis tenuibus confertisque concentrice lamellata.. 

 Margo dorsalis utrinque subrectus, antice paulum, postice modice 

 declivis ; margo ventralis in medio valde arcuatus, postice sinu- 

 atus, et rapide acclivis. Area lunularis impressa ; area do7-salis 

 postica perangusta. 



Long. 1*2, lat. 1 polk 



Hab. ign. {Mus. Hanley), 



The outline of this very rare shell reminds one of the head of a 

 parrot. The beak is placed high up, as in L. gravida. 



y<jt Leptomya spectabilis, sp. nov. 



I T, prci'cedenti similis, sed ovato-acuminata, haud rostrata, sed 



postice subcuneiformis ; margo ventralis simplex et antice sub- 

 arcuatus ; ecctremitas postica infra medium posita. 

 Long. 1-2.5, lat. 0-95 poll. 

 Hab. Japan ? (Mus. Hanley), 



I believe this was the shell supposed by A. Adams to be the 

 L. cochlearis of Hinds, with whose description it fairly accords ; 1 

 found it thus marked in Taylor's collection, which had been largely 

 recruited from Adams's types. 



The name spectabilis was attached to a fine example, classed as 

 a Scrobicularia (it is not that of Philippi) in the British Museum. 



