554 Mr. J. C. Melvill on the 



l)tlpkinula diplacostira* , sp. n. 

 (11. IX. figs. 5, 5 a, bb.) 



D. testa parva, profuode sed anguste umbilioata, albo-stramiuea, 

 solidula, supra planata ; anfractibus quatuor, quorum tresplanati, 

 depressi, simplices, ultimo rapide accrcscente, effuse, apud peri- 

 pheriam acute bicarinato, carinis arete spinicostatis, superficie 

 undiquc longitudinalitcr tenuissime sqnamato-lamellosa ; apertura 

 rotunda ; peristomate extus breviter spinoso, paullum effuso, 

 margine columellari crassiusculo, nitido, albo, ad basin producto, 

 basi circa umbilicum indistincte concentrico-striata, interstitiis 

 undoso-gcmmatis. 



Alt. 3, diam. 6 mm. 



This little species, perhaps not quite fully grown, is distinct 

 from all the others of the genus known to me, in its lamellate 

 longitudinal stride, double periplierial carinations, the upper 

 keel possessing twelve, the lower seventeen coronals of short 

 spines. The umbilicus is very dee|) and narrow, the con- 

 centric sulcation and waved geramse interposing at the base 

 are characteristic, the columellar extension towards the base 

 recalling other Delphinulce. Tlie colour is throughout pale 

 stramineous. D. stellaris, Ad. & Reeve, is perhaps the 

 nearest species in affinity. 



Donax [Serrula) epularis f, sp. n. 

 (Fi. IX. tigs. 6,6 a.) 



D. testa subtrigonali, aequivalvi, ina?quilaterali, alba ; umbonibus 

 parvis, steps violaceis, iucur\-is, approximatis ; margine dorsali 

 autice obliquato, extenso, postice multum abVji eviato, ventrali 

 eubrotuudato, conspicue multidenticulato, superficie omni arete et 

 pulcherrime decussata, costis longitudiualibus latus versus posti- 

 cum magis conspicuis, sed antice ncquaquam evanidis, sulcis 

 spiraliter distinctis prasdita, postico latere pulchre sulcifero et 

 costato, costis breviter spinif'eris, ad marginem bino spinarum 

 longiorum ordine decorato, intus pagiua nitida violaceo-tincta, 

 postice radio nigro-violaceo magis conspicuo, sinu palliali in- 

 definite. 



Alt. 5-50, lat. 8*50, diam. 4 mm. (sp. maj.). 



An exceedingly highly decorated species, though it must 

 be examined with a lens before its characters are very per- 

 ceptible. All the specimens are small, and they have in all 

 probability not yet attained their full growth ; but the sculp- 

 ture is unmistakable and more elaborate than in the other 

 species of this large genus that are comparable with it. 



* SiTiXa^ (TTflpa, with double keel. 

 t Epularis, sumptuous. 



