544 Transactions of the Society. 



specimens of course pass by imperceptible degrees into the type, 

 but two distinct forms are worthy of note as characteristic of this 

 Station, although occasionally found elsewhere. In the first, the 

 wall of the sphere is smooth, and sometimes rather polished, con- 

 structed of homogeneous cement, ranging from bright copper to 

 dark chocolate in colour (PI. XXVI, fig. 9). The second is 

 steel-grey in colour, and with a glazed surface and less prominent, 

 or sometimes hardly perceptible, papillse. The wall of the test in 

 the last form is apparently thickened with micaceous mud, the 

 ]3articles of which are infinitely small (PI. XXVI, fig. 10). Yet 

 another form found at this Station and elsewhere presents a sphere 

 almost devoid of papillse, and nearly black in colour. The shell 

 is constructed of minute and angular sand-grains, giving a glisten- 

 ing appearance to the test. The cement is dark and liberally used 

 (PI. XXVI, fig. 11). 



Brady's figure 7 (pi. xxxvi, Eef. 12) represents a variation 

 which is of fairly frequent occurrence wherever the type prevails, 

 and in which the characteristic papillae are imperforate. In the 

 " Challenger " figure the imperforate papillae are prominent, but 

 this feature is subject to great variation, and in many of the 

 " Goldseeker " specimens the imperforate papillar areas lie practic- 

 ally flush with the surface of the sphere, from which they can be 

 distinguished owing to a difference in colour, which may be due 

 either to a reduction of the thickness of the wall in this area, or 

 to its lesser homogeneity and absence of cement (Plate XXVI, figs. 

 12, 13). These imperforate papillse and papillar areas are, no 

 doubt, permeable to protoplasm and Kemna (Ref. 34) regards them 

 as analogous to the tubules in tlie wall of the perforate Poraminifera. 

 It may be remarked that imperforate papillae and papillar areas are 

 indicated on the interior of the sphere by depressions similar to 

 those on the type, but not perforating the sliell-wall. 



EXPLANATION OF PLATE XXVIII. 



FIGS. 



1-12. — Thuramviina papillata var. haeusleri var. uov. 



Figs. 1. — Compressed specimen, with nmnerous imperforate papillae. 

 Test of clear brown chitin. 

 ,, 2. — Test of cement ; pale chocolate colour ; papillae imperforate 



and few in number. 

 ,, 3. — Arenaceous specimen, largely micaceous ; numerous papillae, 



some perforate. 

 ,, 4, 5. — Chitinous specimens. 

 ,, 6.— Specimen utilizing sponge-spicules largely for construction 



of test. 

 „ 7. — Highly compressed dark chitinous specimen. 

 ,, 8. — Arenaceous specimen. Imperforate papillse arranged in rows 



down three angular edges. 

 ^_ 9. — Specimen with micaceous test on chitinous foundation. 

 „ 10-12. — Coarsely arenaceous specimens. 

 13-16. — T. papillata. Aggregated individuals. (Cf. T. tuberosa Haeusler.) 



17. —T. papillata var. /auosa Flint. Chitinous form. 

 18-21. — T. papillata var wiMrata var. nov. 



All specimens magnified 45 diameters, except fig. 17, which is 90 diameters. 



