50 THE FORAMINIFERA OF THE RIVER DEE. 
‘* CHaRAcTERS.—Test, free, discoidal, spiral; consisting of a non- 
‘* septate tube coiled on itself in one plane. Upper and lower surfaces flat 
‘‘or very slightly concave, studded with minute tubercles; exterior 
‘+ presenting little or no trace of the course of the spiral tube; periphery 
“square. Colour white. Diameter ea inch. 
“This form, which is perhaps a strongly developed variety of Spirillina 
“ margaritifera, was first obtained from deep water off Eddystone, and has 
‘been since found by Mr. Roserrson on other parts of our coast.’ 
A few specimens have been found in the Dee which come 
nearer to this than to avy other known form, but differ from 
it in having only the lower surface tuberculate, while the upper 
surface has the spiral sutural line strongly limbate, and the 
shell perforations numerous and well marked. 
Discorbina biconcava, Parker and Jones. 
Parker and Jones, 1865, North Atlantic and Arctic Foram., p. 422, pl. xix., 
fig. l0abe. — 
A square-edged, bi-concave form, easily distinguished from 
the other Discorbine, but very feeble and rare in the Dee. 
Tinoporus lucidus, Brady, MS. 
Tinoporus lucidus, Brady, 1870, Cat. Brit. Foram. in the Edinburgh 
Museum, p. 8. (No description.) 
This is by no means an uncommon form, and Mr. Brapy’s 
manuscript name has been generally adopted by British rhizo- 
podists. It was originally described in a paper on the “ Rhizo- 
podal Fauna of the Hebrides,” at the meeting of the British 
Association in 1866, the author then regarding it as a species 
of Polytrema, a genus in which it might be placed with almost 
equal justice, but in the doubt which still existed as to its 
affinity, the description did not appear in the abstract of the 
paper. Somewhat later, the same organism was figured by 
Mr. Parrirr as a Polyzoan (Cellepora hemispherica, Ann. and 
Mag. Nat. Hist., 1875, 4 Ser., vol. xii., p. 98, pl. 3 b, fig. 1-6), 
a position to which it has no claim. In the absence of any 
published details, the following characters will serve to identify 
