226 "TERRA NOVA" EXPEDITION. 



due to the greater depth of water in the N.Z. area. We were interested to 

 observe that the Corsican specimens suffered from the depredations of an identical 

 or siiuihxr enemy, many of them being completely riddled with holes and tubular 

 borings. They are probably the w^ork of minute Annelids or Crustacea, which 

 live on the protoplasm of the Polytrema. As to the colouring-matter characteristic 

 of the genus, see page 247. 



609. Polytrema miniaceum, var. alba, Carter. 



Polytrema miniaceum, var. album. Carter, 1877, CB. p. 213, pi. xiii, figs. 14, 15. 



alba, Heron-Allen and Earland, 1914, etc., FKA. 1915, p. 728. 



Station 2. 



At Station 2 unquestionable examples, finely branching and in perfect con- 

 dition, were foimd. At nearly all the other Stations individuals which in the 

 ordinary course would have been ascribed to this variety, owing to their pale 

 colour, occur. At Station 2 a branching specimen of the variety was found, on the 

 broken terminal of one branch of which a young individual of typical red P. minia- 

 ceum had settled down to commence its sessile life, encrusting the var. alhu. At 

 Station G a small individual of typical var. alba as regards the base, passed into 

 pale P. miniaceum in the branching arms ; this appears to us to show that the 

 colour is more or less adventitious. 



Family NUMMULINIDAE. 

 Sub-Family POLYSTOMELLINAE. 



NONIONINA, d'Orbigny. 



610. Nonionina depressula (Walker and Jacob). 



Nautilus depressulus, Walker and Jacob, 1798, AEM. p. G41, pi. xiv, fig. 33. 

 Nonionina depressula, Heron-Allen and Earland, 1914, etc., FKA. 1915, p. 730. 



Stations 1-3, 5, 6, 8-11, 16, 17, 23, 26, 27, 29-31, 33, 36, 38, 45, 47, 48, 

 50, 52, 54, 55 (+ R. d. J., D.). 



Universally distributed and presenting little variation throughout the area, 

 excepting in the deep-water Stations, where the specimens are, as a rule, smaller 

 and more pauperate. At the most southerly Stations, 45-54, the best and most 

 typical series occur. At Station 6, the best in the N.Z area, there is a tendency 

 in many of the specimens to stellate limbation at the umbilicus, giving a super- 

 ficial resemblance to N. stelligera. Fossil examples at Stations 2, 3 and 6. 



[Arenaceous isomorph, Haplophragmium canariense (d'Orb.) pars, = H. nonionin- 

 oides, Ess. (R. 1862, NHC4. p. 30, pi. i. fig. 8).] 



611. Nonionina asterizans (Fichtel and Moll). 



Nautilus asterizans, Fichtel and MoU, 1798, TM. p. 37, pi. iii, figs. e-h. 

 Nonionina „ Heron-Allen and Earland, 1914, etc., FKA. 1915, p. 730. 



Stations 4-8. 10, 54. 



