MOLLUSOA. 41 



ridge, and between this and the first lira and in the interstices 

 between the other lirae the surface is finely striated. The lasi 

 whorl is elongate, has about thirty-one ridges in addition to the 

 minute interstriation. The aperture is narrow, contracted ante- 

 riorly into a short, broadish canal, together equalling almost halt 

 the total length of the shell. The columella is perpendicular, 

 curving a little to the left in front, and coated with a very thin 

 callosity. The labrum is thickened exteriorly, arcuate in the middle, 

 faintly sinuated towards the lower extremity, and rather deeply 

 notched in the slight constriction of the whorl near but not at the 

 suture. 



Length 15 millim., diam. of last whorl above the mouth 1 j ; 

 aperture 7 long. 2 wide. 



Hah. Arafura Sea. X. Australia. 32-36 fms. 



This species is peculiar on account of the absence of longitudinal 

 costa^. The outer lip is smooth in the single specimen at hand, but 

 in other and more mature shells it might be more or less dentate 

 within. 



10. Cythara cylindrica, var. (Plate IY. figs. H-Hl.) 



Mangelia cylindrica. Reeve, Conch. Icon. sp. 9. 

 Var. = 31. lyrica, Reeve, I. c. sp. 30. 



Hah. Port Curtis, 7 fms. (Coppinger) ; Philippine Islands 

 (Owning). 



This species differs from the typical Cythara in having no trans- 

 verse lira? on the columella, in this respect agreeing with C. hom- 

 becJcii, Peeve, C. turricula, Peeve, and C. vit least's, Smith. 



The variety (C. lyrica) is a trifle larger than the normal form, 

 and the riblets are rather stronger at the upper termination. With 

 these feeble distinctions the differences end. In both forms a 

 minute tubercle is sometimes, but not always, met with upon the 

 upper part of the columella, and about fifteen fine lirae may be 

 counted within the exteriorly thickened labrum, which is shallowly 

 sinuated near the suture, and prominently arcuated when viewed 

 laterally. The longitudinal costa? number about fourteen on the 

 penultimate whorl, and the principal transverse thread-like lira? 

 about eight, but upon the last volution there are as many as twenty- 

 six. The entire surface is beautifully cancellated with minute 

 raised lines of growth and microscopic spiral lira?, a feature seen 

 only in well-preserved shells and under a powerful lens. The 

 sculptured whorls are six in number, the remaining two apical ones 

 being smooth and glassy. 



The single specimen, in beautiful condition, from Port Curtis, 

 presents certain differences which it may be as well to mention. 

 At the upper part the whorls exhibit a faint concavity a little 

 beneath the suture, of which I perceive a trace in the type of the 

 species, but not in the variety ( C. lyrica), and the costa? are rather 

 more numerous, there being about 17 upon the penultimate whorl, 



