530 



X. — On some Foraminif era from the North Sea, etc., dredged hy the 

 Fisheries Cruiser " Goldseeker " {International North Sea 

 Investigations — Scotland), v. On Thurammina papillata 

 Brady : a Study in Variation. 



By Edward Heron-Allen, F.L.S. F.Z.S. Pres. E.M.S., 

 and Arthur Earland, F.E.M.S. 



{Bead November 21, 1917.) 

 Plates XXVI.-XXX. 



The genus Thurammina being essentially of deep-water habit is 

 not represented at all in the majority of the " Goldseeker " 

 dredgings, which are from shallow water adjacent to the Scottish 

 coast-line. In some of the dredgings from the deeper areas of the 

 North Sea and off the west of Scotland, however, Thurammina 

 occurs in such abundance and variety as to furnish material suffi- 

 cient for a critical study and revision of this interesting genus. 



A brief synopsis of the published literature of Thurammina 

 appears to be a desirable preliminary to our own remarks on the 

 genus, which was established by Brady in 1879 (Eef. 2), for 

 the reception of specimens discovered in material dredged by 

 the " Challenger." Three species, T. 2^apillata, albicans, and com- 

 vressa, were described, but only the first and last were figured. 

 The genus had probably attracted Brady's attention long previously, 



EXPLANATION OF PLATE XXVI. 



FIGS. 



1, 2. — Chitinous spherules, the earliest free stage of Thurammina pajnllata. 



Papillse absent. 

 3-6. — T. papillata Brady = " Orbuline Lituola'" of Carpenter. Typical aren- 

 aceous spheres in various stages of growth. 

 7, 8.— Chitinous individuals. Colour, purple. Papillae imperforate. 



9. — Sphere type. Chitin and cement. Colour, metallic copper. PapiUae im- 

 perforate. 

 IC. — Sphere type. Built of grey micaceous mud. Papillae minute, sometimes 



imperforate or absent. 

 11. — Sphere type. Large sand-grains and black cement. Papillae absent or 

 very inconspicuous. 

 12, 13. — Sphere type. Finely arenaceous, with imperforate papillae. 



!*• — T. papillata var. castanea var. nov. Purple chitin, with imperforate 

 papillae. 

 15-18. — Ditto. Arenaceous specimens in various stages of development. The 

 prominent papillae are frequently closed at the apex with fine cement. 



All specimens magnified 4-5 diameters. 



