204 '^ TERRA NOVA ' KXPEDlTTOlSr. 



536. Discorbina pilfolus (d'Orbigny). 



Yalvulina pilcohis, d'Orbigny, 1839, FA5I. p. 47, pi. i, fig.s. 15-17. 

 Dixcorhimi ., Brady, 1884, FC. ]). 649, pi. Ixxxix, figs. 2-4. 



Stations 1-6. 



Common everywhere, fos.sils at Stations 2. 3. and 6. This is perliaps tlie 

 species of Discorbina in which budding (or plastogamy) occurs most abundantly. 

 At every Station except Station 4, such pairs occur in profusion, and in every 

 condition from the actual paired shells to disunited specimens in which the whole 

 of the internal septa have been absorbed. There is, in such series, a complete 

 gradation of size in the budded shell from very elementary individuals, to fully- 

 formed tests, and there is a corresponding difference in the proportions of the 

 individuals, a low-domed specimen being often budded from an abnormally high- 

 domed one. (See H.-A. 1915. RPF. p. 246. pi. xv. fig. 27.) 



537. Discorbina ■patelliformis. Brady. 



Discorbina patellifnrmis, Brady, 1884, FC. ]>. (347, pi. Ixxxviii, fig. 3, ]il. Ixxxix, fig, 1. 



Hpron-Allcn and Farland. 1911. clc. FKA. 191.'i. ]). 70.']. pi. jii, fio-, .32. 



Stations 1-3. 5, 6. 



The best at Station 1. Fossils at Stations 2. 3 and 6. Rare everywhere. 



538. Discorbina calcarafa. sp. nov. PI. YII, figs. 12-1 (i. 



Stations 2, 3, 5, 6. 



Test circular, dome-shaped, consisting of two to three convolutions of 

 chambers, six to eight chambers in each convolution. Sutural lines thick, luit 

 not limbate, curving. From the extremity of each sutural line extends a solid 

 spine of very variable dimensions ; sometimes a mere papillation on the marginal 

 edge of the shell, occasionally strong and markedly projecting. Base flat, 

 excavated in the centre, beaded in radiating lines. Surface matt to rough. Apical 

 chamber usually smooth and polished. 



Dimensions: — Width, ■ 20- '30 mm. : height, •20 mm. 



Resembles D. imperatoria (d'Orb.). as figured by Sidebottom (S. 1904, etc.. 

 RFD. 1908, p. 13, pi. V, figs. 1, 2) but is less pointed at the apex, flat instead 

 of concave at the base, and more variable in the character of its spines. The 

 Delos specimens have straight sutural lines. 



Confined to the N.Z. area. At Stations 2 and 3 the spinous development is 

 much more marked than at Stations 5 and 6. Many fossils, but, owing to the 

 nature of the shell-surface, these are not easy to discriminate. 



539. Discorbina harmeri, sp. nov. PI. VII. figs. 9 11. 

 Stations 2-6, 8. 



Test circular, more or less highly domed, rounded at the apex. Very thick- 



