450 Transactions. 



I doubtfully locate here Webster's R. pingue, as the " glossy " proto- 

 conch indicates it as a member of another group ; but it is almost impossible 

 to generically place any Rissoid without study of actual specimens. 



I would reject Alvania without much consideration, and Alvinia super- 

 ficially recalls this group, but the texture differentiates this form easily. 

 I would draw attention to a paper by Bartsch in the Proc. U.S. Nat. Mus., 

 vol. xli, p. 333 et seq., 1911, on the west American species of Alvania. 

 No authority is given for the generic name, nor is there any synonymy 

 collated, nor are comparisons given with any extra-limital forms even as 

 regards generic affinity, yet species with smooth nuclear whorls, punctured 

 (papillose) nuclear whorls, and spirally lirate nuclear whorls are lumped 

 together, whilst the shells show spiral sculpture only or clathrate or both, 

 with varicosed mouths or simple, oval or pear-shaped. 



Alvania cosmia Bartsch, p. 352, pi. 31, fig. 4 ; Alvania halia, id., p. 354, 

 pi. 31, fig. 5 ; and Alvania aequisculpta Keep, p. 358, pi. 32, fig. 7, seem to 

 agree exactly from figures and descriptions with members of Merelina 

 as here proposed, which, as far as Australasian waters are concerned, is a 

 distinct well-marked group. 



Subonoba gen. nov. 



The species Suter classed under Ceratia are here so named, and I select 

 Rissoa fumata as type. In addition to the three species included by Suter, 

 other species are known to me from New Zealand. In general appearance 

 these differ from Onoba, and they always entirely lack longitudinal ribs. 

 The British species of Onoba sometimes show these very obscurely, but 

 even then they are quickly recognizable. 



Probably the shells classed by Hedley in Onoba — viz., Onoba bassiana 

 (Zool. Res. Fish. Exp. "Endeavour," pt. i, p. 108, pi. xix, fig. 25, 1911) and 

 Onoba glomerosa (Proc. Linn. Soc. N.S.W., vol. xxxii, p. 495, pi. xvii, fig. 23, 

 1907) — together with Watson's Rissoa (Onoba) mercurialis (Chall. Rep. Zool., 

 vol. xv, p. 600, pi. xlv, fig. 12, 1886) could be here placed, as, though the 

 two former do not fairly agree in general shape and mouth characters, they 

 disagree much more with typical Onoba. 



Lironoba gen. nov. 



I designate as type of this new group Rissoa suteri Hedley. These 

 heavily lirately sculptured forms seem to be unknown in European seas, 

 as I have noted nothing that much recalled this species. 



When Hedley (Proc. Linn. Soc. N.S.W., vol. xxxiii, p. 469, 1908) 

 described Rissoa imbrex (pi. x, fig. 33) he wrote, " This species is related 

 to a small group of spirally ribbed shells — R. tenisoni Tate, R. layardx 

 Petterd, R. agneivi Ten. -Woods, and R. unilirata Ten.-Woods — among which 

 it stands nearest to the last." Since then he has added Rissoa lockyeri 

 (Zool. Res. Fish. Exp. "Endeavour," pt, i, p. 103, pi. xviii, fig. 22, 1911) 

 and Alvania praetornatilis (Rec. Austr. Mus., vol. viii, p. 139, pi. xli, fig. 16, 

 1912), and this series may be temporarily classed, for the sake of convenience, 

 together under the genus-name Lironoba. I write "temporarily,'* as 

 some recall other genera, and further study may necessitate their trans- 

 position. 



Rissoa wilsonensis Gatliff and Gabriel, Proc. Roy. Soc. Vict., vol. xxv, 

 n.B., p. 68, pi. viii, fig. 4, 1913, also comes into this genus. 



