J1S "TERRA NOVA ' EXPEDITION. 



smaller in proportion to the size of the shell. It seems to me that the fins must be 

 capable of great expansion and retraction, as a vast number of specimens occurred with 

 long, delicate, filmy fins, and very many others were characterized by short, thick, 

 muscular fins. Of course the various preserving fluids* would have a considerable effect 

 as regards this. (Gradations between the two forms could, however, be traced in 

 various hauls. The second and third differences (up. fit. p. 7) referred to the striation 

 and umbilical border of the shell, characters which have already been noted with 

 reference to the " Terra Nova " specimens. It may, however, be added here that some 

 of the larger examples, without shells, have a furrowed appearance just where the early 

 whorls would have rested, suggesting that the shell might have been impressed with 

 deep spiral striae. The fourth difference (op. cit., p. 7) affected the distribution of 

 colour. The present collection is comprised mainly of more or less lemon-coloured 

 specimens. A small minority, about three hundred, are dark brown. This is the hue 

 of all the larger specimens and also of a few quite small ones. The dark colour seems 

 to peel off easily, especially from the edge of the fins and the last whorl of the body 

 which then become white. No yellow specimens exceeded 2 "50 mm. in size. The 

 only haul in which quite dark specimens were associated with the yellow ones occurred 

 at Station 317, August 8, 1911, when four very small dark specimens were observed 

 amongst about a thousand light coloured specimens. One, however, which was 

 dissected seemed to be shrivelled as if it had been allowed to get dry before being put 

 into the tube, and perhaps the dark colour in this instance may be so accounted for. 

 All the other specimens taken from holes in ice, and all occurring in large shoals were 

 light coloured. It seems probable that the dark hue is developed with age, as some of 

 the larger yellow specimens were fawn-coloured, tending towards brownish, particularly 

 at the base of the fins. The species seems to attain its full development, in these 

 regions, during the Antarctic summer from December to February, at which season 

 probably a greater abundance of food is obtainable, All the dark coloured large 

 specimens occurred at this season, and young pale specimens during the months of 

 March, April, May, June and August. An exception to this occurred at Station 269 

 (end of December) when a large take of small pale specimens occurred. Spawning- 

 specimens were observed in a January haul (Station 284). The spawn-masses consisted 

 of a transparent glutinous material connecting many white oblong bodies each of which 

 averaged 132 ju, by 88 p.. 



The fifth difference noted by Sir C. Eliot (/>. cit., p. 7) referred to the posterior 

 lobe of the foot, which he found to be " more deeply and distinctly divided " in 

 L. antarctira than in L. lididna. In " Terra Nova" specimens this is certainly the case 

 compared with Boas' (1886) figure 70 of Table 5, but the figures of Vayssiere (1913, 

 pi. VII, figs. 135 and 136) of the examples of L. heli<-iii from Spitsbergen which he 

 has studied, closely resemble many of the specimens in the present collection. The 



* Most of the specimens were in formalin, a few were in alcohol, and a still smaller number in some other fluid. 



