78 CARBONIFEROUS AND PERMIAN FORAMINIFERA. 



which have burdened this department of zoology names which have had their origin 

 either in deficient observation, or in a disposition to ignore the terms employed by earlier 

 writers. The specimens figured by Messrs. Jones, Parker, and Kirkby, from Permian 

 sources, though generally of larger dimensions than those from Carboniferous beds, are 

 not so characteristic. The tube in the Permian specimens has a larger diameter, but it 

 is correspondingly shorter, and the number of convolutions not so great. 



The Carboniferous examples are usually very minute, often not more than y^oth of an 

 inch (0 % 2 mm.) in diameter, and the test is correspondingly thin and delicate ; but full- 

 sized specimens, such as that represented in PI. Ill, fig. 3, are found sufficiently often to 

 sustain the connection of the series. 



Distribution. Nowhere very common. The only note I have of its occurrence in 

 the English Carboniferous rocks is in the Four-fathom Limestone at Elfhills, Northum- 

 berland. In Scotland it has been found in two or three localities in the Lower Carbonife- 

 rous Limestone Group, and in Belgium in the Calcaire de Namur. 



As a Permian fossil it is confined, so far as is yet ascertained, to the Middle Magnesian 

 Limestone of the North of England. 



TROCHASIMINA PUSILLA (Geinitz). PI. Ill, figs. 4, 5. 



SEKPULA PUSILLA, Geinitz, 1848. Verstein. Zechst. Roth., p. 6, pi. iii, figs. 3 6. 

 FOBAMINITES SERPULOIDES, King, 1848. Cat. Perm. Foss. Northumb., p. 6. 

 SEEPULA? PUSILLA, Jones, 1850. In King's Monogr. Perm. Fossils, p. 57, pi. vi, 



figs. 7 9 ; pi. xviii, figs. 13, a d. 

 SPIRILLINA Jones, 1856. In King, On Irish Permian Fossils, Journ. Geol. 



Soc. Dublin, vol. vii, p. 73, pi. i, figs. 12, a, b. 

 Geinitz, 1861. Dyas, p. 39, pi. x, figs. 1521, and pi. xii, fig. 1. 



MILIOLA(?) Howse and Kirkby, 1863. Synopsis Geol. Durham and North- 



umberland, p. 13. 



SEEPULA Bohche, 1864. Neuea Jahrbuch fur Min., Jahrg. 1864, p. 607. 



TROCHAMMINA PUSILLA, Jones, Parker, and Kirkby, 1869. Ann. and Mag. Nat. Hist., 



ser. 4, vol. iv, p. 390, pi. xiii, figs. 4 6, &c. 



Characters. Shell free, oblong, convoluted ; composed of a non-septate or spuriously 

 septate tube, coiled or doubled on itself more or less regularly, but not on a uniform 

 plane. Aperture taking the form of the open end of the tube ; circular or, where the tube 

 is embracing, crescentic. Length, about ygth inch (2'0 mm.). 



This is an exceedingly abundant and well known Permian fossil, but its zoological 

 affinities, owing to the obscurity and variableness of its characters, have puzzled a sue- 



