MOLLUSCA, I.- SMITH. 75 



45. Li**iir<-ii notorcadensis, Melvill and Standen. var. PI. 1. tigs, in, 17. 



L;*S,H;;, <>>, /,-,/, H.X/X, .M. and S., Voy. " Scotia," Zool., vol. V, p. 114, pi. iijjs. 1 t, MA (1909). 



Stations 11)4. :!14, :',li;. 331, 339, :UO. Depth ranging from 140-457 fathoms. 



The specimens friii 1 1 the above stations differ slightly from typical example's from 

 tin 1 South Orknev Islands. They arc thinner and not <juitc of the same form, the 

 hinge-line being a little shorter, so that the valves have a less broad-shouldered 

 appearance. 



The number of the hinge-teeth is variable. Melvill and Stamlen state that there 

 are " five on each side of the hinge-plate." I have carefullv examined two examples 

 from the South Orknevs, and find in liotli valves six in front of the central ligament 

 and four behind. 



In the " Terra Nova," specimens also similar variation as regards the hinge-teeth 

 is observable, as indicated below. 



Three specimens from Station 331. 



' 



- 



A specimen from Station 194. 



The inner margin of the valves is described as " creuulate," but it should have 

 been stated that on the ventral side, where the byssus would pass between the valves, 

 the edges are smooth. The denticulatiou in the " Scotia" specimens is a little stronger 

 than that of the " Terra Nova " shells. 



Lissarca gourdoni (Lamy*), if not a variety of the present species, is very closely 

 related, and L. /r/y///rAw.s7.<; (Thielef) is hardly separable. The species is probably 

 circumpolar, and exhibits slight modifications in different localities, as indicated by 

 the variation in the "Terra Nova" specimens, from those described from the South 

 Orkneys. 



4(i. Liimopsis iiiiirninciixix. Smith ((). 



six, Smith, " (JhallriiLjcr '' Lami'lliliraiifliiatu, p. ^-")4, pi. X VI II, lij^s. L' I'l: 



(1885). 



Stations 310, 349 : 80-250 fathoms. 



Only two worn dead valves were obtained, and it is consequent I v difficult to 

 determine with certainty to which species thev belong. 



' |)euxii''inc Kxpi'-il. Antarct. Fninraisc ( 1!(IS I!) ID), p. L'l (I'.Ul), as An-it (B,il/n/'i, ,-,i } i/i>nr<liuii. 

 | Ik'Utsrlir SiiiliK.lar I'Xpril., vol. XIII, p. iTi:!, pi. XVIII, lii,'. 7 ll'.ll.'J). 



